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CN116242876B - Heterojunction thermophysical property measuring method and device based on thermal imaging - Google Patents

Heterojunction thermophysical property measuring method and device based on thermal imaging

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Publication number
CN116242876B
CN116242876B CN202211518165.9A CN202211518165A CN116242876B CN 116242876 B CN116242876 B CN 116242876B CN 202211518165 A CN202211518165 A CN 202211518165A CN 116242876 B CN116242876 B CN 116242876B
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temperature rise
average temperature
heterojunction
substrate
test duration
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CN116242876A (en
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曹炳阳
刘智珂
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Tsinghua University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/18—Investigating or analyzing materials by the use of thermal means by investigating thermal conductivity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

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  • Investigating Or Analyzing Materials Using Thermal Means (AREA)

Abstract

The invention provides a thermal imaging-based heterojunction thermophysical property measurement method and device, which comprise the steps of obtaining the thermal conductivity of a substrate of a heterojunction sample to be measured according to an I-th change discrete point in a first test duration based on finite element simulation calculation, obtaining the specific heat of the substrate according to an I-th change discrete point in a second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtaining the interface thermal resistance of the heterojunction sample to be measured and the specific heat of a film according to an II-th change discrete point in a third test duration and the thermal conductivity and the specific heat of the substrate based on finite element simulation calculation, and obtaining the thermal conductivity of the film according to an III-th change discrete point in a fourth test duration and the thermal conductivity and the specific heat of the substrate based on finite element simulation calculation. The invention realizes simultaneous measurement of a plurality of parameters, improves the measurement efficiency, and improves the measurement accuracy by utilizing finite element simulation calculation.

Description

Heterojunction thermophysical property measuring method and device based on thermal imaging
Technical Field
The invention relates to the technical field of semiconductors, in particular to a heterojunction thermophysical property measuring method and device based on thermal imaging.
Background
The solid-state heterostructure is called heterojunction for short, is generally composed of a substrate and an epitaxial layer film, and is composed of metal, semiconductor or insulator, and is widely applied to various advanced technical fields such as power electronics, radio frequency communication, photovoltaic photoelectricity, thermoelectric and the like.
However, with rapid iterations of device performance metrics, heat generation and junction temperature also increase dramatically, which requires devices with good thermal conductivity while having high electron mobility, high breakdown field strength and power. In order to enhance the heat conducting capability of the heterojunction device, researchers have conducted a great deal of thermal analysis and optimization design from the near junction region of the heterojunction device to the external heat dissipation structure, but still cannot fully meet the more severe and complicated thermal management requirements, one of the important reasons is that a high-efficiency method truly suitable for measuring the thermal physical properties of various heterojunctions is still lacking at present.
In the prior art, experimental methods for measuring the thermal physical properties of the heterojunction mainly comprise a time domain thermal reflection method, a Raman spectroscopy method and a 3 omega electrical method.
The time domain thermal reflection method adopts a beam splitter to divide picosecond or femtosecond laser into pumping light and detection light, and derives parameters such as the thermal conductivity and specific heat of a film and a substrate of a detected heterostructure sample, the thermal resistance of an interface between the film and the substrate and the like by fitting the relation between a reflected detection light signal and time delay or modulation frequency. Because the laser repetition frequency of the method reaches the order of 10MHz, the corresponding thermal penetration depth is shallow (100 nm), so that the interface thermal resistance and the substrate thermal conductivity sensitivity of the signal pair of the micro-scale thin film heterostructure with wide application are low, and the test uncertainty is large. The Raman temperature measurement method utilizes Raman spectrum to detect the surface temperature of a specific material, incident photons and atoms are subjected to inelastic scattering, energy exchange is carried out to generate Raman signals, and the change of the material temperature can cause the change of the polarization rate, so that the change affects the Raman signals. Based on the principle, the internal temperature distribution of the sample can be measured, and the thin film of the heterostructure, the thermal conductivity of the substrate, the thermal interface resistance and the like can be derived. The uncertainty of temperature measurement of the method is about 5K, the normal temperature spatial resolution is usually larger than 1 mu m, and the characteristics severely limit the measurement accuracy of the method. For the 3 omega electric method, a strip-shaped metal film needs to be prepared on the surface of a sample to serve as a heating electrode and a detection electrode, alternating current heating is carried out, 3 omega and 2 omega voltage signals of the electrodes are extracted, and related thermophysical properties are derived. However, this approach requires an accurate design of the electrode dimensions to achieve higher sensitivity and is insensitive to specific heat of the material at lower frequencies.
In summary, the heterojunction thermophysical property measurement method in the prior art has the defect of low measurement accuracy and low measurement efficiency.
Disclosure of Invention
The invention provides a thermal imaging-based heterojunction thermophysical property measurement method, which is used for solving the defect of low measurement efficiency of heterojunction thermophysical properties in the prior art and realizing measurement of high specific heat, high thermal conductivity and high interface thermal resistance efficiency and high precision of a film and a substrate of a heterojunction sample.
The invention provides a heterojunction thermophysical property measuring method based on thermal imaging, which comprises the following steps:
Obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be tested in a test duration to obtain I variation discrete points of the I average temperature rise values which vary with time in the test duration;
based on finite element simulation calculation, obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in the first test duration;
Based on finite element simulation calculation, obtaining specific heat of the substrate according to the I-th variation discrete point in the second test duration and the thermal conductivity of the substrate;
acquiring a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of a heterojunction sample to be tested in the test duration to obtain a II variation discrete point of the II average temperature rise value which varies with time in the test duration and a III variation discrete point of the III average temperature rise value which varies with time in the test duration;
based on finite element simulation calculation, obtaining interface thermal resistance of the heterojunction sample to be tested and specific heat of a film according to the II-th variation discrete point in the third test duration and the thermal conductivity and specific heat of the substrate;
Based on finite element simulation calculation, obtaining the thermal conductivity of the film according to the III-th variation discrete point in the fourth test duration, the interface thermal resistance, the specific heat of the film, the thermal conductivity of the substrate and the specific heat;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, in a test duration, a plurality of I-th average temperature rise values of an I-th target area of a heterojunction sample to be measured are obtained to obtain I-th variation discrete points of the I-th average temperature rise value which vary with time in the first test duration, and the method further comprises the following steps:
Arranging a heating electrode on at least part of the surface of the film of the heterojunction sample to be detected, wherein the heating electrode has a preset width;
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
wherein the pulse width of the pulse current is deltat a.
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, based on finite element simulation calculation, the thermal conductivity of the substrate of the heterojunction sample to be measured is obtained according to the I-th variation discrete point in the first test duration, and the method specifically comprises the following steps:
And taking the time range of Deltat a～2Δta after the start of pulse as the first test duration, and obtaining the thermal conductivity k sub of the substrate through univariate inversion according to the I-th variation discrete point based on finite element simulation in the first test duration.
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, based on finite element simulation calculation, specific heat of the substrate is obtained according to the I-th variation discrete point in the second test duration and the thermal conductivity of the substrate, and the method specifically comprises the following steps:
Taking a time range of 0-Deltat a after the pulse starts as the second test duration, and obtaining the specific heat of the substrate through univariate inversion according to the I-th variation discrete point and the thermal conductivity of the substrate based on finite element simulation
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of a heterojunction sample to be measured are obtained, so as to obtain a II variation discrete point of the II average temperature rise value which varies with time in the test duration and a III variation discrete point of the III average temperature rise value which varies with time in the test duration, and the method further comprises the following steps:
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
Wherein the pulse width of the pulse current is deltat b.
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, based on finite element simulation calculation, the interface thermal resistance of the heterojunction sample to be measured and the specific heat of the film are obtained according to the II-th variation discrete point in the third test duration and the thermal conductivity and the specific heat of the substrate, and the method specifically comprises the following steps:
Taking a time range of 0-2Deltat b after pulse start as the third test duration, and obtaining the specific heat of the film through least square inversion according to the II-th variation discrete point, the thermal conductivity and the specific heat of the substrate based on finite element simulation in the third test duration And an interfacial thermal resistance R I of the substrate and the thin film.
According to the thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, based on finite element simulation calculation, the thermal conductivity of the film is obtained according to the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate of the III-th variation discrete point in the fourth test duration, and the method specifically comprises the following steps:
Taking the time range of 0-Deltat b after the pulse starts as the fourth test duration, and obtaining the thermal conductivity k f of the film through univariate inversion according to the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate of the III-th variation discrete point based on finite element simulation.
The invention also provides a heterojunction thermophysical property measuring device based on thermal imaging, which comprises:
the first testing module is used for acquiring a plurality of I-th average temperature rise values of an I-th target area of a heterojunction sample to be tested in a testing duration to obtain I-th variation discrete points of the I-th average temperature rise values which vary with time in the testing duration;
The device comprises a first calculation module, a second calculation module, a third calculation module, a fourth calculation module and a third calculation module, wherein the first calculation module is used for obtaining the heat conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in a first test duration;
The second testing module is used for acquiring a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of the heterojunction sample to be tested in the testing duration to obtain a II variation discrete point of the II average temperature rise value which varies with time in the testing duration and a III variation discrete point of the III average temperature rise value which varies with time in the testing duration;
The second calculation module is used for obtaining the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the film according to the II-th variation discrete point in the third test duration and the thermal conductivity and the specific heat of the substrate based on finite element simulation calculation;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
The invention also provides an electronic device comprising a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes any heterojunction thermophysical property measuring method based on thermal imaging when executing the program.
The present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a thermal imaging based heterojunction thermophysical property measurement method as described in any one of the above.
The thermal imaging-based heterojunction thermophysical property measurement method and device provided by the invention are used for obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be measured in a test duration to obtain an I variation discrete point of the I average temperature rise value changing along with time in the test duration, obtaining the thermal conductivity of a substrate of the heterojunction sample to be measured according to the I variation discrete point in the first test duration based on finite element simulation calculation, obtaining the specific heat of the substrate according to the I variation discrete point in the second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtaining a plurality of II average temperature rise values of the II target area of the heterojunction sample to be measured and a plurality of III average temperature rise values of the III target area in the test duration to obtain a II variation discrete point of the II average temperature rise value changing along with time in the test duration, obtaining a III variation discrete point of the III average temperature rise value of the II average temperature rise value in the test duration, obtaining the thermal conductivity of the substrate to be measured, obtaining the specific heat of the film according to the thermal conductivity of the first interface, the thermal conductivity of the film to be measured according to the finite element simulation calculation, the temperature rise value of the III average temperature rise value in the second test duration and the thermal conductivity of the substrate to be measured, and the thermal conductivity of the film to be measured according to the thermal interface. According to the invention, the heating electrode is arranged on the surface of the film far away from the substrate, the temperature rise changes of different areas of the surface of the sample at different moments are tested by using a thermal imaging method, and the required parameters are obtained by combining finite element simulation calculation, so that the accuracy of parameter measurement is higher. Meanwhile, the method provided by the invention realizes simultaneous measurement of a plurality of parameters, avoids adopting a multi-parameter fitting algorithm, is convenient to solve, and improves the measurement efficiency.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of a thermal imaging-based heterojunction thermophysical property measurement method provided by the invention;
FIG. 2 is a schematic diagram of a cross section of a test sample structure of one embodiment of a thermal imaging based method for measuring thermal physical properties of a heterojunction provided by the present invention;
FIG. 3 is a top view of a test sample structure and test area for one embodiment of a thermal imaging based method for measuring thermal physical properties of a heterojunction provided by the present invention;
FIG. 4 is a schematic waveform diagram of a pulsed square wave heating current of a thermal imaging-based method for measuring thermal physical properties of a heterojunction according to the present invention;
FIG. 5 is a schematic diagram of a thermal imaging-based heterojunction thermophysical property measurement device according to the present invention;
fig. 6 is a schematic diagram of an entity structure of an electronic device according to the present invention.
Reference numerals:
510, 520, 530, 540, respectively, a first test module, a first calculation module, a second test module and a second calculation module;
610 processors 620 communication interfaces 630 memories 640 communication buses.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
A thermal imaging-based method and apparatus for measuring thermal physical properties of a heterojunction according to the present invention are described below with reference to fig. 1-6.
In principle, the reflection thermal imaging method utilizes the functional dependence of the reflectivity of the material and the temperature, derives the reflectivity temperature coefficient according to the reflectivity change per unit temperature change, and obtains the temperature change through the change of the reflected light intensity of the surface of the test device. The illumination light source LED is used for providing incident light with stable light intensity to the surface of the device to be tested, and the Charge Coupled Device (CCD) is used for detecting the reflected light intensity changing along with the temperature. The reflective thermal imaging method has higher spatial resolution (< 300 nm) and higher time resolution (-50 ns), and the imageable material range comprises metals and semiconductors commonly used in electronic devices.
Infrared thermal imaging methods utilize the principle of infrared radiation. Any object with a limited temperature can radiate electromagnetic waves, the intensity of which depends on their temperature and emissivity. The infrared thermometer collects electromagnetic waves with infrared wavelength, and the temperature of a sample can be extracted according to the Planck blackbody radiation law. To map the temperature profile of the sample surface, an infrared array detector is used in an infrared microscope, each pixel converting infrared radiation into a single pixel resistance change and then into a two-dimensional temperature profile. The technology is a non-contact, nondestructive and convenient method and has extremely fast imaging capability. The temperature resolution can be described by Noise Equivalent Temperature Difference (NETD), which determines the minimum temperature difference that can be detected, and infrared thermometry NETD can now reach the mK magnitude.
Therefore, the reflection thermal imaging method and the infrared thermal imaging method can carry out two-dimensional space and one-dimensional time integrated temperature test on the heterostructure sample, can be used for simultaneously measuring the specific heat, the thermal conductivity and the interface thermal resistance of the film and the substrate of the heterojunction sample, and improves the characterization efficiency and accuracy.
Fig. 1 is a schematic flow chart of a thermal imaging-based heterojunction thermophysical property measurement method provided by the invention, as shown in fig. 1, the method comprises the following steps:
step 110, obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be tested in a test duration to obtain I variation discrete points of the I average temperature rise values which vary with time in the test duration.
As shown in fig. 2, the heterojunction sample structure to be tested comprises an insulating layer 201, a thin film 202, an interface 203, and a substrate 204. In one embodiment of the present application, the material of the insulating layer is not particularly limited, and in particular, the insulating layer is selected from at least one of silicon dioxide, hafnium oxide, zirconium dioxide, aluminum oxide, gallium oxide, and silicon nitride, and one skilled in the art can select the thermal conductivity and specific heat of the insulating layer of the test sample according to the method of the present application according to actual needs.
The material of the thin film is limited to a hard solid material with a forbidden bandwidth of less than or equal to 3.40eV, and specifically, the thin film may be a gallium nitride thin film, a gallium arsenide thin film, a silicon thin film, a germanium thin film, a molybdenum disulfide thin film, a silicon carbide thin film, a gallium arsenide thin film, an indium arsenide thin film, an aluminum arsenide thin film, a gallium phosphide thin film, an indium phosphide thin film, a zinc oxide thin film, a zinc telluride thin film, a titanium dioxide thin film, or the like. According to some embodiments of the present invention, the thickness of the thin film is not particularly limited, and for example, the thickness of the thin film may be 50nm to 20 μm. Therefore, the sensitivity of temperature rise change to the specific heat of the substrate, the thermal conductivity and the interface thermal resistance is prevented from being influenced by the excessive thickness of the film.
The material of the substrate is not particularly limited, and the hard solid material may be tested by the above-mentioned method, and specifically to the present invention, the material of the substrate includes at least one of a non-radioactive inorganic non-metal solid material, a non-radioactive inorganic metal solid material, a non-radioactive organic non-metal solid material, and a non-radioactive organic metal solid material. Specifically, the substrate is selected from at least one of gallium nitride, aluminum nitride, tantalum nitride, gallium oxide, aluminum oxide, sapphire, silicon, germanium, silicon germanium alloy, silicon dioxide, quartz, silicon carbide, silicon nitride, diamond, graphite, high-orientation pyrolytic graphite, boron arsenide, gallium arsenide, indium arsenide, aluminum gallium arsenide, aluminum arsenide, gallium phosphide, indium phosphide, zinc oxide, hafnium dioxide, titanium nitride, magnesium oxide, lithium niobate, strontium titanate, strontium ruthenate, and mica, and composites thereof. According to some embodiments of the present invention, the thickness of the substrate is not particularly limited, and for example, the thickness of the substrate may be 10 μm to 1cm. Thereby, the substrate thickness is prevented from being too thin and from breaking during the test.
In operation, the heating electrode 205 is first disposed on at least a portion of the surface of the film 202 remote from the substrate 204, and has a width W h, and the structure is described with reference to fig. 2 and 3. And then a pulse square wave heating current is connected to the heating electrode, the amplitude of the pulse square wave heating current is I a, the pulse width of the pulse square wave heating current is delta t a,Δta, the first pulse duration is the first pulse duration, the duty ratio of the pulse square wave heating current is d a, and the pulse waveform is shown in fig. 4. And measuring the I-th average temperature rise delta T 1 of the sample surface area I at a certain position in the width direction of the heating electrode by using a thermal imaging method to obtain a discrete point of change of delta T 1 along with time, namely an I-th discrete point of change.
Wherein the area I is in the range of distance from the heating electrode l 1～l1+Δl1. The distance parameter l 1 may be 3 μm to 8 μm, and ΔI 1 may be 2 μm to 7 μm.
The amplitude I a of the pulse square wave heating current can be 50 mA-500 mA, the pulse width delta t a can be 200 ns-50 mu s, and the duty ratio d a can be 0.5% -10%.
Thermal imaging methods include reflectance thermal imaging methods and infrared thermal imaging methods.
In some embodiments of the present invention, in the reflection thermal imaging method, an LED light source with a wavelength λ a is selected, where the light source wavelength λ a may be 340nm to 780nm, specifically, 340nm,365nm,405nm,455nm,470nm,505nm,530nm, 650 nm,780nm, and the like, and the actual selection may be according to the reflectance temperature coefficient (C th) of the material at the wavelength, and the selection of the wavelength corresponding to the higher absolute value of C th may be accomplished by referring to literature or actual calibration. The reflected heat light source has a preset distance from the heterojunction sample to be tested.
In some embodiments of the present invention, in the infrared thermal imaging method, the infrared radiation detected by the infrared array detector may be mid-wave infrared (with a wavelength range of 3-5 μm) or long-wave infrared (with a wavelength range of 7.5-13.5 μm).
And 120, obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in the first test duration based on finite element simulation calculation.
And in the first test duration, obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested based on finite element simulation calculation after obtaining the I-th variation discrete point. The finite element simulation is to construct a model with the same structure as an actual sample in a computer, set the same heat flow and temperature boundary conditions, simulate the real situation of the measured sample, and calculate the corresponding thermophysical parameters.
And 130, obtaining the specific heat of the substrate according to the I-th variation discrete point in the second test duration and the thermal conductivity of the substrate based on finite element simulation calculation.
In the actual operation process, after the I-th variation discrete point and the thermal conductivity of the substrate are obtained in the second test duration, the specific heat of the substrate is obtained based on finite element simulation calculation.
And 140, acquiring a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of the heterojunction sample to be tested in the test duration to obtain II variation discrete points of the II average temperature rise values which change with time in the test duration and III variation discrete points of the III average temperature rise values which change with time in the test duration.
After the thermal conductivity of the substrate of the heterojunction sample to be detected and the specific heat of the substrate are obtained, pulse square wave heating current is conducted to the heating electrode, the amplitude of the pulse square wave heating current is I b, the pulse width of the pulse square wave heating current is delta t b,Δtb, the second pulse duration is the duty ratio of the pulse square wave heating current is d b. Using a thermal imaging method, as shown in fig. 3, the II-th average temperature rise Δt 2 from the region II at a certain position in the width direction of the heating electrode and the III-th average temperature rise Δt 3 from the region III at a certain position in the width direction of the heating electrode were measured to obtain variation discrete points of Δt 2 and Δt 3 with time, i.e., the II-th variation discrete point and the III-th variation discrete point.
Region II is in a range from the heating electrode l 2～l2+Δl2, and region III is in a range from the heating electrode l 3～l3+Δl3. The distance parameter l 2 may be 1 μm to 5 μm, and Δl 2 may be 1 μm to 4 μm. The distance parameter l 3 may be 5 μm to 10 μm, and Δl 3 may be 1 μm to 4 μm.
The amplitude I b of the pulse square wave heating current can be 50 mA-500 mA, the pulse width delta t b can be 200 ns-50 mu s, and the duty ratio d b can be 0.5% -10%.
In some embodiments of the present invention, in the reflection thermal imaging method, an LED light source with a wavelength λ b is selected, where the light source wavelength λ b may be 340nm to 780nm, specifically, 340nm,365nm,405nm,455nm,470nm,505nm,530nm, 650 nm,780nm, and the like, and the actual selection may be according to the reflectance temperature coefficient (C th) of the material at the wavelength, and the selection of the wavelength corresponding to the higher absolute value of C th may be accomplished by referring to literature or actual calibration. The reflected heat light source has a preset distance from the heterojunction sample to be tested.
In some embodiments of the present invention, in the infrared thermal imaging method, the infrared radiation detected by the infrared array detector may be mid-wave infrared (with a wavelength range of 3-5 μm) or long-wave infrared (with a wavelength range of 7.5-13.5 μm).
And 150, obtaining the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the film according to the II-th variation discrete point in the third test duration and the thermal conductivity and the specific heat of the substrate based on finite element simulation calculation.
And in the third test time period, obtaining the II-th variation discrete point and the III-th variation discrete point, and then obtaining the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the film based on finite element simulation calculation.
160, Based on finite element simulation calculation, obtaining the thermal conductivity of the film according to the interface thermal resistance, the specific heat of the film, the thermal conductivity of the substrate and the specific heat of the III-th variation discrete point in the fourth test duration;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
And in the fourth test duration, obtaining the thermal conductivity of the film according to the II-th variation discrete point, the interface thermal resistance, the specific heat of the film, the thermal conductivity of the substrate and the specific heat.
In some embodiments, obtaining a plurality of ith average temperature rise values of an ith target area of a heterojunction sample to be tested in a test duration to obtain an ith variation discrete point of the ith average temperature rise value varying with time in the first test duration, and before:
Arranging a heating electrode on at least part of the surface of the film of the heterojunction sample to be detected, wherein the heating electrode has a preset width;
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
wherein the pulse width of the pulse current is deltat a.
Specifically, a heating electrode 205, the width of which is denoted as W h, is provided on at least a portion of the surface of the film remote from the substrate, and the sample structure is described with reference to fig. 2 and 3. And then a pulse square wave heating current is connected to the heating electrode, the amplitude of the heating current is I a, the pulse width of the heating current is delta t a,Δta, the first pulse duration is the first pulse duration, and the duty ratio of the heating current is d a. After the thermal conductivity of the substrate of the heterojunction sample to be detected and the specific heat of the substrate are obtained, pulse square wave heating current is conducted to the heating electrode, the amplitude of the pulse square wave heating current is I b, the pulse width of the pulse square wave heating current is delta t b,Δtb, the second pulse duration is the duty ratio of the pulse square wave heating current is d b. The pulse waveform is referred to in fig. 4. In some embodiments of the present invention, the width W h of the heating electrode may be 2 μm to 10 μm.
In one embodiment of the invention, if the material of the film has better insulativity, the wide heating electrode, the narrow heating electrode and the detection electrode can be directly arranged on the surface of the film, and if the material forming the film has better conductivity, the insulating layer can be arranged on the surface of the film, thereby playing the role of preventing electrode crosstalk and electric leakage.
The material of the heating electrode is not particularly limited and is selected from electrode materials commonly used in the art, for example, the heating electrode in the present application is at least one selected from Au, pt, pd, ag, cr, ni, ti, cu and Al each independently.
In some embodiments, based on finite element simulation calculation, obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in the first test duration specifically includes:
And taking the time range of Deltat a～2Δta after the start of pulse as the first test duration, and obtaining the thermal conductivity k sub of the substrate through univariate inversion according to the I-th variation discrete point based on finite element simulation in the first test duration.
Specifically, in the time range of the first test duration after the pulse starts, the thermal conductivity k sub of the substrate is obtained according to the I-th variation discrete point through univariate inversion based on finite element simulation. That is, the first test duration is the time range of Δt a～2Δta after the start of the pulse, at which time the pulse is stopped and the heating electrode temperature falls back. And obtaining the thermal conductivity k sub of the substrate according to the I-th variation discrete point through univariate inversion in the time range of deltat a～2Δta of pulse stop.
In some embodiments, based on finite element simulation calculations, obtaining the specific heat of the substrate from the discrete point of variation I and the thermal conductivity of the substrate within a second test duration specifically includes:
Taking a time range of 0-Deltat a after the pulse starts as the second test duration, and obtaining the specific heat of the substrate through univariate inversion according to the I-th variation discrete point and the thermal conductivity of the substrate based on finite element simulation
Specifically, after obtaining the thermal conductivity of the substrate, obtaining the specific heat of the substrate according to the I-th variation discrete point and the thermal conductivity of the substrate by single variable inversion based on finite element simulation in the time range of the second test duration after the pulse startsThat is, the second test duration is a time range of 0 to Δt a after the start of the pulse, at this time, the pulse starts, the heating electrode starts to work, and the temperature of the heterojunction sample to be tested increases. In the time range of 0-Deltat a from the beginning of the pulse, obtaining the specific heat of the substrate according to the I-th variation discrete point and the thermal conductivity of the substrate through univariate inversion based on finite element simulation
In some embodiments, obtaining a plurality of II average temperature rise values of a II target region and a plurality of III average temperature rise values of a III target region of a heterojunction sample to be tested to obtain a II variation discrete point where the II average temperature rise value varies with time in the test duration and a III variation discrete point where the III average temperature rise value varies with time in the test duration, further includes:
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
Wherein the pulse width of the pulse current is deltat b.
Specifically, after obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested and the specific heat of the substrate, a pulse square wave heating current is connected to the heating electrode, the amplitude of the square wave heating current is I b, the pulse width of the square wave heating current is deltat b,Δtb, the second pulse duration is d b, and the duty ratio of the square wave heating current is d b. The pulse waveform is referred to in fig. 4. In some embodiments of the present invention, the width W h of the heating electrode may be 2 μm to 10 μm.
In some embodiments, based on finite element simulation calculation, obtaining the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the thin film according to the II-th variation discrete point in the third test duration and the thermal conductivity and the specific heat of the substrate specifically includes:
Taking a time range of 0-2Deltat b after pulse start as the third test duration, and obtaining the specific heat of the film through least square inversion according to the II-th variation discrete point, the thermal conductivity and the specific heat of the substrate based on finite element simulation in the third test duration And an interfacial thermal resistance R 9 of the substrate and the thin film.
Specifically, in the time range of the third test duration after the pulse starts, based on finite element simulation, obtaining the specific heat of the film through least square inversion according to the II-th variation discrete point, the thermal conductivity and the specific heat of the substrateAnd an interfacial thermal resistance R I of the substrate and the thin film. The third test duration is a time range of 0-2 Δt b after the start of the pulse, at this time, the pulse starts from 0 time and continues at b, then the pulse stops for Δt b, the heating electrode works in a time range of 0- Δt b, the temperature of the heterojunction sample to be tested rises for Δt b, then the pulse stops in a time range of Δt b～2Δtb, and the temperature of the heterojunction sample to be tested drops (drops) for Δt b. In the time range of 0-2Deltat b after the pulse starts, based on finite element simulation, obtaining the specific heat of the film through least square inversion according to the II-th variation discrete point, the thermal conductivity and the specific heat of the substrateAnd an interfacial thermal resistance R I of the substrate and the thin film.
In some embodiments, based on finite element simulation calculation, obtaining the thermal conductivity of the thin film according to the interface thermal resistance, the specific heat of the thin film, and the thermal conductivity and specific heat of the substrate at the III-th variation discrete point in the fourth test duration specifically includes:
Taking the time range of 0-Deltat b after the pulse starts as the fourth test duration, and obtaining the thermal conductivity k f of the film through univariate inversion according to the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate of the III-th variation discrete point based on finite element simulation.
Specifically, specific heat of the film is obtainedAnd after interface thermal resistance R I of the substrate and the film is carried out, obtaining the thermal conductivity k f of the film through univariate inversion according to the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate in the time range of the fourth test duration after the pulse starts based on finite element simulation. That is, the fourth test duration is a time range of 0 to Δt b after the start of the pulse, at this time, the pulse starts from time 0, Δt b is continued, the heating electrode works, and the heterojunction sample to be tested heats up. And in the time range of 0-Deltat b from the beginning of the pulse, based on finite element simulation, obtaining the thermal conductivity k f of the film through univariate inversion according to the III-th variation discrete point, the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate.
Based on the above embodiments, the present invention provides an illustration of performing one measurement using the thermal imaging based heterojunction thermophysical property measurement method described above.
The method comprises the following steps of (1) setting an insulating layer on one side of gallium nitride far away from silicon carbide, wherein an epitaxial growth 2 mu m gallium nitride heterojunction sample on a silicon carbide substrate, the insulating layer is made of aluminum oxide, the thickness is 50nm, setting a heating electrode on the surface of the insulating layer far away from a gallium nitride film, and measuring specific heat and thermal conductivity and interface thermal resistance of the film and the substrate of the heterojunction sample by adopting a reflection thermal imaging method:
(1) A heating electrode having a width of 5 μm is provided on at least a portion of the surface of the film remote from the substrate.
(2) And a pulse square wave heating current is connected to the heating electrode, the amplitude of the heating current is 200mA, the pulse width of the heating current is 10 mu s, and the duty ratio of the heating current is 5%. And (3) using a reflection thermal imaging method to select an LED light source with the wavelength of 365nm, and measuring an I-th average temperature rise value delta T 1 of a sample surface area I at a certain position in the width direction of the heating electrode to obtain an I-th variation discrete point of delta T 1 along with time. Wherein the range of the area I is 5-10 mu m away from the heating electrode. Obtaining the thermal conductivity k sub of the substrate to be 340 W.m -1·K-1 through univariate inversion based on finite element simulation in the time range of 10 mu s-20 mu s after the pulse starts, obtaining k sub, and obtaining the specific heat of the substrate through univariate inversion based on finite element simulation in the time range of 0-10 mu s after the pulse starts675 J.kg -1K-1.
(3) And a pulse square wave heating current is connected to the heating electrode, the amplitude of the heating current is 280mA, the pulse width of the heating current is 800ns, and the duty ratio of the heating current is 2%. By using a reflection thermal imaging method, an LED light source with a wavelength of 365nm is selected, and the II-th average temperature rise Deltat 2 of the area II at a certain position in the width direction of the heating electrode and the III-th average temperature rise Deltat 3 of the area III at a certain position in the width direction of the heating electrode are measured to obtain II-th variation discrete points and III-th variation discrete points of Deltat 2 and Deltat 3 along with time. Wherein the range of the area II is 2-4 mu m from the heating electrode, and the range of the area III is 8-10 mu m from the heating electrode. In the time range of 0-1.6 mu s after the pulse starts, obtaining the specific heat of the film through least square inversion based on finite element simulation470 J.kg -1K-1, obtaining interface thermal resistance R I of 12m 2K·GW-1 of the substrate and the filmAnd after R I, obtaining the thermal conductivity k f of the film to be 180W m -1K-1 through univariate inversion based on finite element simulation in the time range of 0-800 ns after the pulse starts.
The final test results are shown in Table 1.
TABLE 1 final test results
In summary, through the experimental results shown in the above table 1, it can be seen that the method provided by the application can realize accurate measurement of specific heat and thermal conductivity of the heterostructure film and the substrate and interface thermal resistance, and the measurement result accords with the reference value range of the literature, thereby proving the practicability and reliability of the method.
In the specific embodiment, the thermal imaging-based heterojunction thermophysical property measurement method is used for obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be tested in a test duration to obtain I variation discrete points of the I average temperature rise values which change with time in the test duration, obtaining the thermal conductivity of a substrate of the heterojunction sample to be tested according to the I variation discrete points in a first test duration based on finite element simulation calculation, obtaining the specific heat of the substrate according to the I variation discrete points in a second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtaining a plurality of II average temperature rise values of the II target area of the heterojunction sample to be tested and a plurality of III average temperature rise values of the III target area in the test duration to obtain II variation discrete points of the II average temperature rise values which change with time in the test duration, obtaining the III average temperature rise values of the III variation discrete points in the test duration, obtaining the thermal conductivity of the substrate according to the first thermal conductivity, obtaining the thermal conductivity of the film according to the first thermal conductivity, the second thermal conductivity, the first thermal conductivity and the thermal conductivity of the film, and the thermal conductivity of the film. The method has the advantages that the heating electrode is arranged on the surface of the film far from the substrate, the pulse square wave heating current is connected, the temperature rise changes of different areas on the surface of the sample at different moments are tested by utilizing the thermal imaging method, the required parameters are obtained by combining finite element simulation calculation, the simultaneous measurement of a plurality of parameters is realized, only the pulse current is utilized for heating, only limited times of tests are needed, the test flow is efficient and quick, the sensitivity of the temperature rise changes of different areas and different time periods to different physical properties is utilized, the thermal physical properties are gradually inverted, the adoption of a multi-parameter fitting algorithm is avoided, and the solving precision is improved.
The thermal imaging-based heterojunction thermophysical property measuring device provided by the invention is described below, and the thermal imaging-based heterojunction thermophysical property measuring device and the thermal imaging-based heterojunction thermophysical property measuring method described above can be correspondingly referred to each other.
Fig. 5 is a schematic structural diagram of a thermal imaging-based heterojunction thermophysical property measurement device according to the present invention, as shown in fig. 5, including a first test module 510, a first calculation module 520, a second test module 530, and a second calculation module 540.
Wherein:
The first test module 510 is configured to obtain, in a test duration, a plurality of ith average temperature rise values of an ith target area of a heterojunction sample to be tested, so as to obtain an ith variation discrete point where the ith average temperature rise value varies with time in the test duration;
The first calculation module 520 is configured to obtain a thermal conductivity of a substrate of the heterojunction sample to be tested according to the I-th variation discrete point in a first test duration based on finite element simulation calculation;
a second testing module 530, configured to obtain, in the testing period, a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of a heterojunction sample to be tested, so as to obtain a II variation discrete point where the II average temperature rise value varies with time in the testing period, and a III variation discrete point where the III average temperature rise value varies with time in the testing period;
The second calculation module 540 is configured to obtain, based on finite element simulation calculation, an interfacial thermal resistance of the heterojunction sample to be tested and a specific heat of a thin film according to the II-th variation discrete point in a third test duration and the thermal conductivity and the specific heat of the substrate;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
Based on the above embodiment, in the device, in a test period, a plurality of ith average temperature rise values of an ith target area of a heterojunction sample to be tested are obtained, so as to obtain an ith variation discrete point of the ith average temperature rise value which varies with time in the first test period, and before the step, the step further includes:
Arranging a heating electrode on at least part of the surface of the film of the heterojunction sample to be detected, wherein the heating electrode has a preset width;
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
wherein the pulse width of the pulse current is deltat a.
Based on the above embodiment, in the device, based on finite element simulation calculation, the thermal conductivity of the substrate of the heterojunction sample to be tested is obtained according to the I-th variation discrete point in the first test duration, and specifically includes:
And taking the time range of Deltat a～2Δta after the start of pulse as the first test duration, and obtaining the thermal conductivity k sub of the substrate through univariate inversion according to the I-th variation discrete point based on finite element simulation in the first test duration.
Based on the above embodiment, in the device, based on finite element simulation calculation, the specific heat of the substrate is obtained according to the I-th variation discrete point in the second test duration and the thermal conductivity of the substrate, and specifically includes:
Taking a time range of 0-Deltat a after the pulse starts as the second test duration, and obtaining the specific heat of the substrate through univariate inversion according to the I-th variation discrete point and the thermal conductivity of the substrate based on finite element simulation
Based on the above embodiment, in the device, a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of a heterojunction sample to be tested are obtained, so as to obtain a II variation discrete point where the II average temperature rise value varies with time in the test duration and a III variation discrete point where the III average temperature rise value varies with time in the test duration, which further includes:
Switching on a pulse square wave heating current with preset parameters to the heating electrode;
Wherein the pulse width of the pulse current is deltat b.
Based on the above embodiment, in the device, based on finite element simulation calculation, according to the II-th variation discrete point in the third test duration and the thermal conductivity and specific heat of the substrate, the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the thin film are obtained, which specifically includes:
Taking a time range of 0-2Deltat b after pulse start as the third test duration, and obtaining the specific heat of the film through least square inversion according to the II-th variation discrete point, the thermal conductivity and the specific heat of the substrate based on finite element simulation in the third test duration And an interfacial thermal resistance R I of the substrate and the thin film.
Based on the above embodiment, in the device, based on finite element simulation calculation, the thermal conductivity of the thin film is obtained according to the interfacial thermal resistance, the specific heat of the thin film, and the thermal conductivity and specific heat of the substrate at the III-th variation discrete point in the fourth test duration, which specifically includes:
Taking the time range of 0-Deltat b after the pulse starts as the fourth test duration, and obtaining the thermal conductivity k f of the film through univariate inversion according to the interface thermal resistance, the specific heat of the film and the thermal conductivity and specific heat of the substrate of the III-th variation discrete point based on finite element simulation.
In the specific embodiment, the thermal imaging-based heterojunction thermophysical property measuring device provided by the invention obtains a plurality of I average temperature rise values of an I target area of a heterojunction sample to be measured in a test duration to obtain an I variation discrete point of the I average temperature rise value changing along with time in the test duration, obtains the thermal conductivity of a substrate of the heterojunction sample to be measured according to the I variation discrete point in the first test duration based on finite element simulation calculation, obtains the specific heat of the substrate according to the I variation discrete point in the second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtains a plurality of II average temperature rise values of an II target area of the heterojunction sample to be measured and a plurality of III average temperature rise values of an III target area in the test duration to obtain a II variation discrete point of the II average temperature rise value changing along with time in the test duration and a III variation discrete point of the III average temperature rise value in the test duration, and obtains the thermal conductivity of the film according to the thermal conductivity of the first thermal conductivity, and the thermal conductivity of the film, and the thermal interface. The method has the advantages that the heating electrode is arranged on the surface of the film far from the substrate, the pulse square wave heating current is connected, the temperature rise changes of different areas on the surface of the sample at different moments are tested by utilizing the thermal imaging method, the required parameters are obtained by combining finite element simulation calculation, the simultaneous measurement of a plurality of parameters is realized, only the pulse current is utilized for heating, only limited times of tests are needed, the test flow is efficient and quick, the sensitivity of the temperature rise changes of different areas and different time periods to different physical properties is utilized, the thermal physical properties are gradually inverted, the adoption of a multi-parameter fitting algorithm is avoided, and the solving precision is improved.
Fig. 6 illustrates a physical schematic diagram of an electronic device, which may include a processor 610, a communication interface communications interface, a memory 630, and a communication bus 640, as shown in fig. 6, where the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 may call logic instructions in the memory 630 to perform a thermal imaging-based method of measuring a thermal physical property of a heterojunction, the method comprising obtaining a plurality of I-th average temperature rise values of an I-th target region of a heterojunction sample to be tested over a test period of time to obtain I-th variation discrete points of the I-th average temperature rise values over time over the test period of time; obtaining the thermal conductivity of a substrate of a heterojunction sample to be tested according to the I-th variation discrete point in a first test duration based on finite element simulation calculation, obtaining the specific heat of the substrate according to the I-th variation discrete point in a second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtaining a plurality of II-th average temperature rise values of a II-th target area and a plurality of III-th average temperature rise values of a III-th target area of the heterojunction sample to be tested in the test duration to obtain a II-th variation discrete point of the II-th average temperature rise value, which varies with time in the test duration, and a III-th variation discrete point of the III-th average temperature rise value, which varies with time in the test duration, based on finite element simulation calculation, obtaining the interfacial thermal resistance and specific heat of a thin film of the heterojunction sample to be tested according to the II-th variation discrete point in a third test duration and the thermal conductivity and specific heat of the substrate based on finite element simulation calculation, obtaining the interfacial thermal resistance and the specific heat of the thin film according to the III-th variation discrete point in a fourth test duration, obtaining the thermal conductivity of the thin film, and the thermal conductivity of the thin film based on finite element simulation calculation The II average temperature rise value and the III average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
Further, the logic instructions in the memory 630 may be implemented in the form of software functional units and stored in a computer-readable storage medium when sold or used as a stand-alone product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. The storage medium includes a U disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, an optical disk, or other various media capable of storing program codes.
In yet another aspect, the present invention further provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements to perform the thermal imaging-based method for measuring a thermal physical property of a heterojunction provided by the above methods, the method comprising obtaining, over a test period, a plurality of I-th average temperature rise values of an I-th target region of a heterojunction sample to be measured, to obtain an I-th variation discrete point at which the I-th average temperature rise value varies over time over the test period; obtaining the thermal conductivity of a substrate of a heterojunction sample to be tested according to the I-th variation discrete point in a first test duration based on finite element simulation calculation, obtaining the specific heat of the substrate according to the I-th variation discrete point in a second test duration and the thermal conductivity of the substrate based on finite element simulation calculation, obtaining a plurality of II-th average temperature rise values of a II-th target area and a plurality of III-th average temperature rise values of a III-th target area of the heterojunction sample to be tested in the test duration to obtain a II-th variation discrete point of the II-th average temperature rise value, which varies with time in the test duration, and a III-th variation discrete point of the III-th average temperature rise value, which varies with time in the test duration, based on finite element simulation calculation, obtaining the interfacial thermal resistance and specific heat of a thin film of the heterojunction sample to be tested according to the II-th variation discrete point in a third test duration and the thermal conductivity and specific heat of the substrate based on finite element simulation calculation, obtaining the interfacial thermal resistance and the specific heat of the thin film according to the III-th variation discrete point in a fourth test duration, obtaining the thermal conductivity of the thin film, and the thermal conductivity of the thin film based on finite element simulation calculation The II average temperature rise value and the III average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method.
The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.
It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present invention.

Claims (10)

1. A thermal imaging-based method for measuring thermal physical properties of a heterojunction, comprising:
Obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be tested in a test duration to obtain I variation discrete points of the I average temperature rise values which vary with time in the test duration;
based on finite element simulation calculation, obtaining the thermal conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in the first test duration;
Based on finite element simulation calculation, obtaining specific heat of the substrate according to the I-th variation discrete point in the second test duration and the thermal conductivity of the substrate;
acquiring a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of a heterojunction sample to be tested in the test duration to obtain a II variation discrete point of the II average temperature rise value which varies with time in the test duration and a III variation discrete point of the III average temperature rise value which varies with time in the test duration;
based on finite element simulation calculation, obtaining interface thermal resistance of the heterojunction sample to be tested and specific heat of a film according to the II-th variation discrete point in the third test duration and the thermal conductivity and specific heat of the substrate;
Based on finite element simulation calculation, obtaining the thermal conductivity of the film according to the III-th variation discrete point in the fourth test duration, the interface thermal resistance, the specific heat of the film, the thermal conductivity of the substrate and the specific heat;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method;
Obtaining a plurality of I average temperature rise values of an I target area of a heterojunction sample to be tested in a test duration to obtain I variation discrete points of the I average temperature rise values which vary with time in the first test duration, wherein the method further comprises the following steps:
Arranging a heating electrode on at least part of the surface of the film of the heterojunction sample to be tested;
The range of the first target area is 3-8 mu m from the heating electrode l 1～l1+Δl1;l1, 2-7 mu m from Deltal 1, the range of the second target area is 1-5 mu m from the heating electrode l 2～l2+Δl2,l2, 1-4 mu m from Deltal 2, and the range of the third target area is 5-10 mu m from the heating electrode l 3～l3+Δl3,l3, 1-4 mu m from Deltal 3.
2. The thermal imaging-based heterojunction thermophysical property measurement method of claim 1, wherein obtaining a plurality of ith average temperature rise values of an ith target area of a heterojunction sample to be measured in a test duration to obtain an ith variation discrete point of the ith average temperature rise value varying with time in the first test duration, further comprises:
Wherein the heating electrode has a preset width;
Switching on a first pulse square wave heating current with preset parameters to the heating electrode;
Wherein the pulse width of the first pulse square wave heating current is 。
3. The thermal imaging-based heterojunction thermophysical property measurement method of claim 2, wherein obtaining the thermal conductivity of the substrate of the heterojunction sample to be measured according to the I-th variation discrete point in the first test duration based on finite element simulation calculation specifically comprises:
After starting with pulse ~In the first test duration, obtaining the thermal conductivity of the substrate through univariate inversion according to the I-th variation discrete point based on finite element simulation。
4. The thermal imaging-based heterojunction thermophysical property measurement method of claim 2, wherein obtaining the specific heat of the substrate from the I-th variation discrete point and the thermal conductivity of the substrate in a second test period based on finite element simulation calculation, specifically comprises:
with pulse start 0 to Based on finite element simulation, obtaining the specific heat of the substrate through univariate inversion according to the I-th variation discrete point and the thermal conductivity of the substrate。
5. The thermal imaging-based heterojunction thermophysical property measurement method of claim 1, wherein obtaining a plurality of II-th average temperature rise values of a II-th target region and a plurality of III-th average temperature rise values of a III-th target region of a heterojunction sample to be measured to obtain a II-th variation discrete point of the II-th average temperature rise value varying with time in the test duration and a III-th variation discrete point of the III-th average temperature rise value varying with time in the test duration, further comprises:
switching on a second pulse square wave heating current with preset parameters to the heating electrode;
wherein the pulse width of the second pulse square wave heating current is 。
6. The thermal imaging-based heterojunction thermophysical property measurement method of claim 5, wherein obtaining the interface thermal resistance of the heterojunction sample to be measured and the specific heat of the thin film according to the II-th variation discrete point in the third test duration and the thermal conductivity and specific heat of the substrate based on finite element simulation calculation specifically comprises:
with pulse start 0 to In the third test duration, based on finite element simulation, obtaining the specific heat of the film according to the thermal conductivity and specific heat of the II-th variation discrete point and the substrate by least square inversionAnd interfacial thermal resistance of the substrate and the film。
7. The thermal imaging-based heterojunction thermophysical property measurement method of claim 5, wherein obtaining the thermal conductivity of the thin film according to the interface thermal resistance, the specific heat of the thin film and the thermal conductivity and specific heat of the substrate at the III-th variation discrete point in the fourth test period based on finite element simulation calculation specifically comprises:
with pulse start 0 to Based on finite element simulation, obtaining the thermal conductivity of the film according to the III-th variation discrete point, the interface thermal resistance, the specific heat of the film, the thermal conductivity of the substrate and the specific heat through univariate inversion。
8. A thermal imaging-based heterojunction thermophysical property measurement device, comprising:
the first testing module is used for acquiring a plurality of I-th average temperature rise values of an I-th target area of a heterojunction sample to be tested in a testing duration to obtain I-th variation discrete points of the I-th average temperature rise values which vary with time in the testing duration;
The device comprises a first calculation module, a second calculation module, a third calculation module, a fourth calculation module and a third calculation module, wherein the first calculation module is used for obtaining the heat conductivity of the substrate of the heterojunction sample to be tested according to the I-th variation discrete point in a first test duration;
The second testing module is used for acquiring a plurality of II average temperature rise values of a II target area and a plurality of III average temperature rise values of a III target area of the heterojunction sample to be tested in the testing duration to obtain a II variation discrete point of the II average temperature rise value which varies with time in the testing duration and a III variation discrete point of the III average temperature rise value which varies with time in the testing duration;
The second calculation module is used for obtaining the interface thermal resistance of the heterojunction sample to be tested and the specific heat of the film according to the II-th variation discrete point in the third test duration and the thermal conductivity and the specific heat of the substrate based on finite element simulation calculation;
the first average temperature rise value, the second average temperature rise value and the third average temperature rise value are obtained by measuring the surface of the heterojunction sample to be measured through a thermal imaging method;
in the device, a plurality of I-th average temperature rise values of an I-th target area of a heterojunction sample to be tested are obtained in a test duration to obtain I-th variation discrete points of the I-th average temperature rise values, which vary with time in the first test duration, and the device further comprises:
Arranging a heating electrode on at least part of the surface of the film of the heterojunction sample to be tested;
The range of the first target area is 3-8 mu m from the heating electrode l 1～l1+Δl1;l1, 2-7 mu m from Deltal 1, the range of the second target area is 1-5 mu m from the heating electrode l 2～l2+Δl2,l2, 1-4 mu m from Deltal 2, and the range of the third target area is 5-10 mu m from the heating electrode l 3～l3+Δl3,l3, 1-4 mu m from Deltal 3.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the thermal imaging-based heterojunction thermophysical property measurement method of any one of claims 1 to 7 when the program is executed by the processor.
10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the thermal imaging-based heterojunction thermophysical property measurement method of any one of claims 1 to 7.
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