HK1087530A - Method for introduing impurities - Google Patents

Description

Impurity introduction method

Technical Field

The present invention relates to an impurity introducing method for introducing impurities in a manufacturing process of a semiconductor or the like.

Background

On the surface of the solid substrate or the surface of the thin film, a film of an oxide in which atoms constituting the solid substrate are bonded to oxygen in the air or a film terminated with hydrogen is generally formed. Such films are very thin, typically 1nm or less. Conventionally, impurities have been physically introduced by ion implantation or the like from above a film of an oxide or the like. That is, the impurities are introduced into the solid matrix by applying energy to the ions to be the impurities by an electric field or the like and irradiating the surface with the energy.

However, with the miniaturization of devices in recent years, techniques for forming shallow junctions have been demanded. Here, a low-energy ion implantation technique is an example of a conventional technique for forming a shallow junction. The low-energy ion implantation technique is a method of extracting ions from an ion source at a certain high voltage and then decelerating the ions at a later stage, and studies have been made to maintain a certain level of current value of the ion beam and to perform low-energy implantation. As a result of such studies, a shallow impurity layer of about several tens of nm can be formed, and the method has been industrially applied to the manufacture of semiconductors.

In addition, plasma doping is a technique that has recently attracted attention in order to form a shallow junction. The plasma doping technique is a technique of introducing impurities into a surface of an object to be processed, such as a semiconductor substrate, by bringing plasma containing desired particles into contact with the surface. Here, since the plasma has a low energy of at most several hundred V, it is suitable for forming a shallow impurity layer, and an experiment for forming a shallow junction from tens of nm to several tens of nm has been conducted.

Also, an experiment to achieve the shallowest P-type junction that is currently available is disclosed in "Technical Digest of Symposium on VLSI technology. The depth of the experimental junction is reported to be 7 nm.

In addition, in (1) International works on Junction Technology (IWJT), p.19(2000), (2) J.Vac.Sci.technology.A16, P.1, (1998), (3) silicon Technology-No. 3918^thA gas phase doping method using a gas source is proposed in June, 2002, etc. This is a method of heating a semiconductor substrate in an atmospheric hydrogen atmosphere and supplying B₂H₆Or pH₃And forming P-type and N-type impurity diffusion layers. Here, the hydrogen carrier gas removes a natural oxide film on silicon to maintain a clean surface, and has an effect of suppressing surface segregation of impurities, particularly boron.

In addition, a temperature of 600 ℃ or higher is generally required for decomposing the gas. For example, in "silicon technology" (No. 3918)^thJune, 2002) by heating a semiconductor substrate to 900 ℃ and supplying 1ppm of B for 40 seconds₂H₆Experimental results of gas to form shallow junctions at high concentration. Accordingly, the boron concentration is set to 1X 10¹⁸cm^-3When the depth of (2) is regarded as the junction depth, the junction depth is about 7nm, which is about the same as the above.

Further, a technique of implementing a gas phase doping method at room temperature is disclosed in International Workshop on Junction Technology (IWJT), p.39-40 (2002). This is a method of introducing a substance into a solid substrate having a film of an oxide or the like attached to the surface thereof, removing the film of the oxide or the like, and then attaching or introducing desired particles. According to the report, the depth of the impurity introduced layer is about 3 to 4 nm.

As described above, experiments for forming shallow junctions from tens of nm to several tens of nm have been carried out in recent years by using plasma doping, low-energy ion implantation, or the like. In the experiment for realizing the shallowest P-type junction in the prior art, a shallow impurity layer of about 7nm is formed. However, as devices are further miniaturized, it is required to provide a method of forming a shallower impurity layer more simply and with lower resistance.

As a technique for meeting such a demand, a plasma doping technique can introduce particles into a semiconductor substrate with small acceleration energy, and therefore can form an introduction layer shallower than ion implantation. However, although the energy is small, there is a limit to forming a shallow introduction layer because of the acceleration energy. In addition, it is proposed to supply radicals (radial) as a dopant to the substrate during plasma doping. Since the radicals do not have electric charges, the radicals are not injected into the substrate by being accelerated between the sheaths (sheath), but are activated, and thus are considered to be introduced into the substrate by reacting with the substrate surface. The gas phase doping method using a gas source is a technique of supplying a dopant having no acceleration energy to a substrate and forming an impurity diffusion layer by using a surface reaction. This technique is considered to be a technique that exceeds the limit of the method of irradiating ions having energy onto a substrate.

However, as described above, in the gas phase doping method using a gas source, a temperature of 600 ℃ or higher is generally required for decomposing the gas. Photoresist cannot be used as a mask material at such high temperatures. For this purpose, it is necessary to form SiO by CVD₂And the like, and thus there is a problem that the number of steps of the transistor forming process increases.

Further, when a dopant having no or very small acceleration energy such as radicals or gas molecules in the plasma doping method or the gas phase doping method is introduced into the substrate, there is a problem that it is difficult to form a high-concentration impurity layer in a short time.

Further, the gas phase doping method, which is a method of removing a film of an oxide or the like and then attaching or introducing desired particles, has a problem that a method of controlling the amount of impurities has not been proposed, although a high-concentration impurity layer can be formed at room temperature.

As a technique for amorphizing (amorphizing) crystalline silicon which is a semiconductor substrate, a method of ion-implanting germanium or silicon has been proposed in the past. There have been widely studied processes in which germanium or silicon is ion-implanted into a silicon substrate to make the surface amorphous, and then an impurity such as boron is ion-implanted, followed by an annealing step. The advantages of performing amorphization in advance before ion implantation of impurities are as follows. (1) When a small impurity such as boron is ion-implanted, it is difficult to implant the impurity deeply, and (2) amorphous silicon has a higher light absorption coefficient than crystalline silicon, and therefore, the impurity can be effectively activated during annealing.

However, the amorphization by ion implantation has a problem that the efficiency of forming a shallow amorphous layer is insufficient.

Disclosure of Invention

The method for introducing an impurity of the present invention is characterized by comprising: a step of forming an amorphous layer on the surface of a solid substrate; and forming a shallow impurity-introduced layer on the amorphized semiconductor substrate; the step of forming an amorphous layer is a step of irradiating the surface of the semiconductor substrate with plasma, and the step of forming a shallow impurity-introduced layer is a step of introducing an impurity into the surface which is amorphized. Furthermore, the present invention is characterized in that: further comprises a step of annealing the substrate after the introduction of the impurity to electrically activate the impurity.

The impurity introducing apparatus of the present invention is an impurity introducing apparatus of an apparatus group including at least an apparatus for amorphizing a surface of a solid substrate, an apparatus for introducing desired particles to become impurities, and an annealing apparatus for activating the introduced impurities.

Drawings

Fig. 1 is a sectional view of the main part of an apparatus of one embodiment of the present invention.

Fig. 2 is a view showing a cross-sectional TEM observation result of a substrate according to an embodiment of the present invention.

Fig. 3 is a graph showing the plasma irradiation bias voltage dependence of the thickness of the amorphous layer according to an embodiment of the present invention.

FIG. 4 is a graph showing the results of RHEED observation according to the present invention.

FIG. 5 is a graph showing the results of RHEED observation in comparative examples.

FIG. 6 is a graph comparing sheet resistance values for one embodiment of the present invention and a comparative example.

Fig. 7 is a graph showing the plasma irradiation time dependence of the sheet resistance value according to the embodiment of the present invention.

Fig. 8 is a graph showing the bias voltage dependence of the sheet resistance value according to the embodiment of the present invention.

Fig. 9 is a graph showing the relationship between the sheet resistance value and the amorphous layer thickness according to one embodiment of the present invention.

Detailed Description

The impurity introducing method according to the present invention is characterized in that desired particles as impurities are impregnated, adhered, or introduced (hereinafter, referred to as introduced) after an amorphous layer is formed by irradiating plasma on the surface of a solid substrate, or while the amorphous layer is formed on the surface of the solid substrate. The reason for this is that desired particles can be easily introduced into the solid matrix by forming the amorphous layer. In addition, when applied to a silicon substrate which is one of solid substrates, amorphous silicon has a higher absorption coefficient of light than crystalline silicon, and therefore, by forming an amorphous layer on the surface, impurities can be activated efficiently during annealing, and a low resistance of an extremely shallow junction can be achieved.

In the case where an extremely shallow amorphous layer is formed on the surface of the solid substrate, it is preferable to irradiate plasma to the solid surface. This is because a shallow amorphous layer can be formed more efficiently because a low-energy plasma is used as compared with the amorphization by conventional ion implantation. Among the effects of the amorphous layer, when it is intended to utilize only the effect that impurities are easily introduced in an ultra-low energy state such as a gas or a radical, the formation of the amorphous layer can be achieved by at least one method selected from the group consisting of a method of irradiating plasma to a solid surface, a method of ion-implanting into a solid surface, and a method of adding an amorphous layer to a solid surface. It is preferable to set the time for irradiating the plasma to the solid surface to less than 70 seconds because a good throughput can be achieved. In addition, Ge ion implantation is preferable because improvement of electrical characteristics can be expected in ion implantation.

Preferably, the impurity is introduced by bringing a gas or plasma containing desired particles into contact with the surface of the amorphized solid substrate to impregnate, attach or introduce the impurity to the surface of the solid substrate or the vicinity thereof. The reason is that a shallow impurity layer can be formed only by contacting particles such as gas or plasma which do not have acceleration energy or have very small acceleration energy. Specifically, plasma, radical, gas, ultra-low energy ion, and the like can be given. As a specific name of the method of introducing an impurity, gas doping is referred to when the impurity is introduced in a gas state, and plasma doping is referred to when plasma is brought into contact with the surface of a solid substrate. In addition, in the case of amorphization by ion implantation, novelty can be achieved by utilizing a method capable of introducing impurities with ultra-low energy in addition to annealing efficiently. Specifically, in the case of amorphization by ion implantation, a method of bringing a gas into contact with the surface of a solid substrate is used for introduction of impurities. By this method, a very shallow impurity-introduced layer can be formed.

A method of introducing impurities by controlling and adjusting the thickness of the surface of the solid substrate subjected to amorphization and the degree of amorphization to control and adjust the dose amount and junction depth is preferable because the sheet resistance value can be easily controlled and the device characteristics can be easily controlled. The thickness of the surface of the solid substrate to be amorphized and the degree of amorphization can be controlled and adjusted by changing the bias voltage, irradiation time, bias power (bias power), ion type, and sheath voltage related to the plasma irradiated to the solid surface.

Preferably the plasma comprises a noble gas such as argon, helium or hydrogen. The reason for this is that since the rare gas is chemically stable and hardly chemically reacts with the surface of the solid substrate, it is considered that the ratio of the desired particles to the surface of the solid substrate is suppressed to be small. As a result, it is expected that impurities due to surface adsorption can be introduced in addition to impurities due to amorphization. Helium and hydrogen are preferable because they have a large diffusion coefficient at high temperatures and a small amount of residue on the surface after annealing, and thus hardly have an electrical adverse effect. Helium is particularly preferred because it has both the characteristics of being chemically stable and having a large diffusion coefficient at high temperatures.

The impurity introducing apparatus of the present invention is an impurity introducing apparatus of an apparatus group including at least an apparatus for amorphizing a surface of a solid substrate, an apparatus for introducing desired particles, and an annealing apparatus for activating the introduced desired particles, and can realize the process of the present invention.

Further, it is preferable from the viewpoint of improving productivity and the like because a device set including 2 or more devices for amorphizing the surface of the solid substrate, a device for introducing desired particles, and an annealing device for activating the introduced desired particles can be combined or integrated to make the device compact.

Further, it is possible to provide a method for forming an impurity layer which can form a very shallow impurity layer having a high concentration in a short time, can control the dose more easily than the conventional method, and can reduce the sheet resistance after annealing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.

Fig. 1 illustrates an apparatus 100 used in one embodiment of the present invention. The apparatus 100 has: a high-frequency power supply 1; a matching box 2; a coil and antenna 3; mass flow controllers 4 and 5; a turbomolecular pump 6; an electrically conductive valve 7; a drying pump 8; a circulator 9; a DC power supply 10; a matching box 11, a high-frequency power supply 12 and a lower electrode 14. An object to be processed 13 such as a silicon substrate is placed on the lower electrode.

In fig. 1, after the silicon substrate 13 is sent into the process chamber 15, it is set on the lower electrode 14. A rare gas inlet pipe 16 and a diborane gas inlet pipe 17 are connected to the process chamber 15. In addition, the rare gas is used to amorphize the surface of the silicon substrate by irradiating the surface with a rare gas plasma. The diborane gas is used for plasma doping or gas doping by introducing the gas into the process chamber 15 as it is. The gas flow rates can be controlled by the mass flow controllers 4 and 5, respectively.

In the following examples, the surface amorphization of the solid substrate itself is illustrated. However, the present invention is not limited to this, and can be applied to the surface of a thin film formed on a solid substrate.

(example 1)

In example 1, a process of forming an amorphous layer by plasma irradiation will be described in detail.

In the process chamber 15, plasma is irradiated to a silicon substrate as the object to be processed 13.

The gas used was argon, helium or 99.975% helium mixed with 0.025% diborane.

First, an argon plasma was irradiated to a silicon substrate. The plasma irradiation conditions were performed under conditions of an irradiation time of from 5 seconds to 60 seconds and a bias voltage of from 30V to 310V. After the plasma irradiation is stopped and the inside of the process chamber 15 is first evacuated, the substrate is taken out from the process chamber 15 after purging with nitrogen gas. And a TEM observation was made on the cross section of the taken-out substrate. Fig. 2 is a cross-sectional TEM photograph of the argon plasma after irradiation with the plasma at a bias voltage of 180V for a plasma irradiation time of 5 seconds. It can be seen that an amorphous layer 22 of thickness 4.3nm has been formed on the silicon substrate 21.

Further, even in the case of using helium plasma, the formation of an amorphous layer can be confirmed. In addition, the case of using helium plasma is described in example 2.

Plasma irradiation was performed for 60 seconds at a bias voltage of 100V using plasma of a mixed gas of 99.975% helium gas and 0.025% diborane gas. The thickness of the amorphous layer was 10 nm. Further, the boron dose measured by SIMS was 7.3X 10¹⁴cm^-2. As described above, the formation of the amorphous layer and the introduction of the impurity can be performed simultaneously.

(example 2)

In example 2, the control of the thickness of the amorphous layer used in the irradiation of the amorphizing plasma is described.

A silicon substrate as an object to be processed 13 is irradiated with plasma of helium gas having a helium gas concentration of 100% in a process chamber 15. Plasma irradiation was performed under conditions in which the plasma irradiation time was 7 seconds and 30 seconds, respectively, and the bias voltage was varied within a range from 30V to 310V. The thickness of the amorphous layer of the substrate taken out of the process chamber 15 was measured by an ellipsometer. Fig. 3 is a graph of bias voltage versus thickness of an amorphous layer. It was found that an amorphous layer in the range of 2nm to 22nm could be formed in a short time of 30 seconds or less under plasma irradiation. Further, the thickness of the amorphous layer can be controlled by varying the bias voltage. Further, the thickness of the amorphous layer can be changed by changing the time for which plasma is irradiated.

(example 3)

In example 3, an example in which the impurity introduction method of the present invention is applied to gas doping is shown. In the case of introducing impurities by gas doping, the difference in sheet resistance value due to the presence or absence of an amorphous layer was investigated. Next, the following describes that impurities can be easily introduced with low energy by amorphization and that resistance can be reduced after annealing.

In the process chamber 15, argon plasma is irradiated to a silicon substrate as the object to be processed 13. The plasma irradiation was performed under the conditions of plasma irradiation time of 5 seconds and bias voltage of 160V. After stopping plasma irradiation and evacuating the inside of the process chamber 15, B is allowed to stand₂H₆The gas was in contact with the substrate surface for 70 seconds. Stop B after 70 seconds₂H₆After the gas supply is vacuumized, the substrate is taken out from the process chamber 15 after purging with nitrogen gas.

After annealing the substrate taken out at 1100 f for 3 minutes, the sheet resistance value was measured by the 4-probe method. Further, observation with RHEED and measurement of film thickness with an ellipsometer were performed for the substrate subjected to only plasma irradiation. Among them, RHEED is Reflection High-Energy Electron Diffraction (Reflection High-Energy Electron Diffraction).

Fig. 4 shows the results of surface observation with RHEED. As shown in fig. 4, no specific bright point was found on the crystal, and it was seen that the surface of the substrate was amorphized by plasma irradiation. Further, the sheet resistance value was 5.1E3 ohm/sq.

In addition, the same experiment was performed by changing the plasma irradiation time in the range of 5 seconds to 70 seconds and changing the bias voltage in the range of 45V to 210V. The substrate surface has been amorphized under all conditions. In this case, the sheet resistance value is distributed in a range of 6.5E2ohm/sq or more and 5.1E3ohm/sq or less.

Fig. 6 is a diagram showing a difference in Sheet resistance value (Sheet resistance) depending on the presence or absence of an amorphous layer. The sheet resistance measurement results of the present example in which the amorphization was performed are indicated by white circles (. smallcircle.). Meanwhile, the result of comparative example 1 in which amorphization was not performed is indicated by a black circle (●). The sheet resistance values of the examples were distributed to values smaller by 1 order of magnitude to 2 order of magnitude than those of the comparative examples. It is considered that since the amorphous layer is formed, B is easily introduced into the matrix without supplying acceleration energy₂H₆Gas, and by efficient absorptionThe sheet resistance value of the light collected for annealing was greatly reduced as compared with the comparative example.

(example 4)

In example 4, a difference in sheet resistance value due to the presence or absence of an amorphous layer when plasma doping was used as an introduction method of an impurity was examined. The case where the junction depth after annealing is the same but the resistance can be lowered by the amorphization will be described.

In order to amorphize the surface of the silicon substrate, the silicon substrate as the object to be processed 13 is irradiated with plasma of helium gas having a helium gas concentration of 100% in the process chamber 15. The plasma irradiation was carried out under conditions of a plasma irradiation time of 7 seconds and a bias voltage of 150V. After the plasma irradiation is stopped, the inside of the process chamber 15 is evacuated. Then, for plasma doping, B diluted to 5% with helium gas was irradiated under a bias voltage of 200V for 7 seconds₂H₆A plasma of gas. After the plasma irradiation was stopped and the vacuum was applied, the substrate was taken out from the process chamber 15 after purging with nitrogen gas. Then, annealing was performed under the conditions of peak high-speed thermal annealing (spike RTA) in which the temperature increase rate was 200 ℃/sec, the temperature decrease rate was 50 ℃/sec, and the maximum reaching temperature was 1000 ℃ in order to electrically activate the impurities. The sheet resistance and SIMS distribution of the thus-prepared sample were measured.

The sheet resistance of this sample was 635 ohm/sq. When set in the SIMS distribution, the boron concentration becomes 1X 10¹⁸cm^-3When the depth of (A) is the junction depth, the junction depth is 27.2 nm. On the other hand, as will be described in detail in comparative example 2, the sample prepared under the same conditions without amorphization had a sheet resistance value of 923ohm/sq and a junction depth of 28.1 nm. That is, by performing amorphization by helium plasma irradiation, a low resistance of 30% or more can be achieved even if the junction depth is substantially the same.

(example 5)

In example 5, the relationship between the plasma irradiation time and the sheet resistance value was examined. Fig. 7 shows the results.

A silicon substrate as the object to be processed 13 is irradiated with plasma of argon gas in the process chamber 15. The argon plasma irradiation varied the plasma irradiation time in the range from 5 seconds to 70 seconds. The bias voltage was set to be 45V (indicated by X) and 160V (indicated by ■) under 2 conditions. The treatment after the plasma irradiation was performed under the same conditions. That is, after the plasma irradiation is stopped and the inside of the process chamber 15 is evacuated, B is set to be₂H₆The gas was in contact with the substrate surface for 70 seconds. Stop B after 70 seconds₂H₆After evacuation, the substrate is taken out from the process chamber 15 after purging with nitrogen gas. The substrate taken out was annealed at 1100 f for 3 minutes, and then the sheet resistance value was measured by the 4-probe method.

In both cases of the bias voltage of 45V and 60V, the sheet resistance value decreases as the plasma irradiation time becomes longer. From the results, it can be seen that the sheet resistance value can be controlled by changing the plasma irradiation time.

In addition, the above experimental results show that the longer the plasma irradiation time, the higher the dose. This is considered to be because the longer the plasma irradiation time is, the higher the degree of amorphization of the silicon substrate surface is, and therefore B₂H₆The more the gas is introduced into the substrate.

(example 6)

In example 6, the relationship between the bias voltage and the sheet resistance value was examined. Fig. 8 shows the results. When the argon plasma irradiation time was set to 70 seconds and other conditions were the same, samples were prepared by changing the bias voltages to 45V (sample 1), 160V (sample 2), and 210V (sample 3). The conditions not particularly specified were the same as in example 5.

As shown in fig. 8, the sheet resistance value decreases as the absolute value of the bias voltage increases. As a result, the sheet resistance values of samples 2 and 3 were reduced to 1.0E3ohm/sq or less.

It follows that the sheet resistance value can be controlled by varying the bias voltage.

Furthermore, the above experimental results show that the larger the absolute value of the bias voltage, the higher the dose. This is considered to be because the larger the absolute value of the bias voltage is, the higher the degree of amorphization of the silicon substrate surface becomes, and B is₂H₆The amount of gas introduced into the substrate increases.

(example 7)

In example 7, the relationship between the thickness of the amorphous layer and the sheet resistance value was examined. Fig. 9 shows the results. The thickness of the amorphous layer on the horizontal axis is a value of the thickness of the amorphous layer formed on the substrate surface of the samples 1 to 3 prepared in example 6 measured by an ellipsometer. The data indicating that the thickness of the amorphous layer is zero are the measurement results when the silicon substrate was measured as a comparative example.

As shown in FIG. 9, the thickness of the amorphous layer was 2nm in sample No. 1 and about 3nm in samples No. 2 and No. 3. Further, it can be seen that the sheet resistance value decreases as the thickness of the amorphous layer increases. From the results, it is seen that the sheet resistance value can be controlled by changing the thickness of the amorphous layer. Further, it can be seen that the degree of amorphization described in examples 5 and 6 can be expressed as the thickness of the amorphous layer.

In addition, the above experimental results indicate that the larger the thickness of the amorphous layer, the higher the dose. It is considered that this is because B is increased as the thickness of the amorphous layer is larger₂H₆Amount of gas introduced into the substrate.

Comparative example 1

Experiments were performed under the same conditions as in examples 3, 5, 6, and 7, which represent embodiments of the present invention, except that amorphization was not performed by plasma irradiation. Comparative example 1 is an example relating to gas doping, and corresponds to example 3. After the silicon substrate is placed in the process chamber 15 and the process chamber 15 is evacuated, B is allowed to stand₂H₆The gas was in contact with the substrate surface for 70 seconds.

At 7Stop B after 0 second₂H₆After the gas is supplied and evacuated, the substrate is taken out from the process chamber 15 after nitrogen purging. The substrate taken out was annealed at 1100 f for 3 minutes, and then the sheet resistance value was measured using a 4-probe. In addition, the boron dose was measured by a Secondary Ion mass spectrometry (hereinafter referred to as SIMS). Further, the surface of the silicon substrate before introduction into the process chamber 15 was observed and measured by RHEED and ellipsometer.

Fig. 5 is a surface observation result with RHEED of the silicon substrate of the comparative example. Bright spots were observed in the upper part of the photograph shown in fig. 5, and it was confirmed that the photograph was crystalline. Further, the amorphous layer on the surface could not be confirmed even by ellipsometry.

Further, the sheet resistance value was 1.7E5 ohm/sq. This value is larger by 1 order of magnitude or more than that of the sheet resistance value of the present embodiment in which the amorphous layer is formed. The boron dose was 2E12cm-2 as determined by SIMS. It was found that almost no impurities were introduced.

Comparative example 2

An experiment was performed under the same conditions as in inventive example 4, except that the amorphization was not performed by plasma irradiation. That is, a silicon substrate as the object to be processed 13 is placed in the process chamber 15. Then, for plasma doping, B diluted to 5% with helium gas was irradiated at a bias voltage of 200V for 7 seconds₂H₆A plasma of gas. After stopping the plasma irradiation and evacuating, the substrate is taken out from the process chamber 15 after purging with nitrogen gas. Then, annealing was performed under spike RTA conditions of a temperature rise rate of 200 ℃/sec, a temperature fall rate of 50 ℃/sec and a maximum reaching temperature of 1000 ℃ in order to electrically activate the impurities. The sheet resistance and SIMS distribution of the thus-prepared sample were measured.

The sheet resistance of this sample was 923ohm/sq, and the junction depth was 28.1 nm. This is a 30% or more higher sheet resistance than the amorphized sample of example 3.

Although the amorphization of the surface of the solid base itself is described in the examples, the surface of the solid base of the present invention includes a surface of a thin film formed on the base in addition to the surface of the base itself. Therefore, amorphization of the surface of a thin film formed on a solid substrate is also included in the scope of the present invention.

As described above, the impurity introduction method of the present embodiment can form a very shallow impurity layer at room temperature in a short time, and can easily manufacture active elements such as semiconductors, liquid crystals, and biochips, and passive elements such as resistors, coils, and capacitors.

Industrial applicability.

As described above, the present invention provides an impurity introduction method capable of forming a very shallow impurity layer with a high concentration in a short time at room temperature, easily controlling the dose, and forming an impurity layer capable of reducing the sheet resistance after annealing.

Claims (21)

1. An impurity introducing method, comprising:

a step 1 of forming an amorphous layer on the surface of a solid substrate; and

a 2 nd step of forming a shallow impurity-introduced layer on the amorphized solid substrate;

wherein the step 1 is a step of irradiating the surface of the solid substrate with plasma,

the step 2 is a step of introducing impurities into the surface of the amorphized solid substrate.

2. The method of introducing an impurity according to claim 1, wherein: the above-mentioned 2 nd step is a step of plasma doping the impurity.

3. The method of introducing an impurity according to claim 1, wherein: the above-mentioned 2 nd step is a step of ion-implanting impurities.

4. The method of introducing an impurity according to claim 1, wherein: the above-mentioned 2 nd step is a step of gas doping the impurity.

5. The method of introducing an impurity according to claim 1, wherein: the second step may be followed by an annealing step of activating the impurity.

6. The method of introducing an impurity according to claim 1, wherein: the 1 st step is performed before the 2 nd step, or simultaneously with the 2 nd step.

7. The method of introducing an impurity according to claim 1, wherein: the above-described 1 st step and the above-described 2 nd step are performed as continuous steps in-situ in the same process chamber.

8. The method of introducing an impurity according to claim 1, wherein: the first step 1 is a step of irradiating the surface of the solid substrate with plasma, or a step of adding an amorphous layer to the solid substrate.

9. The method of introducing an impurity according to claim 8, wherein: the solid substrate is silicon, and the step 1 is a step of controlling the thickness of the amorphous layer by changing at least one of a bias voltage, an irradiation time, a bias power, an ion type, and a sheath voltage with respect to plasma irradiated onto the surface of the solid substrate.

10. The method of introducing an impurity according to claim 9, wherein: the plasma irradiation time is 5 seconds or more and less than 70 seconds.

11. The method of introducing an impurity according to claim 8, wherein: the plasma is a plasma of a system containing at least one selected from a rare gas, hydrogen, and a halogen.

12. The method of introducing an impurity according to claim 1, wherein:

the step 1 is a step of performing ion implantation on the surface of the solid substrate,

the step 2 is a step of introducing the impurity into the surface of the amorphized solid substrate by gas doping.

13. The method of introducing an impurity according to claim 12, wherein: the ion implantation is performed by implanting at least one ion selected from Si and Ge.

14. The method of introducing an impurity according to claim 1, wherein: the 2 nd step is a step of bringing a gas or plasma containing the desired particles into contact with the amorphous layer, and introduces the particles as impurities onto the surface of the solid substrate.

15. The method of introducing an impurity according to claim 1, wherein: in the 2 nd step, desired particles are introduced in the state of plasma, radicals, gas, or ions.

16. An impurity introducing method, comprising: a step of irradiating the surface of the solid substrate with plasma for 5 seconds or longer and less than 70 seconds; and an impurity introduction step of bringing at least one selected from a gas containing desired particles, plasma, radicals, and ions into contact with the surface of the solid substrate.

17. The method of introducing an impurity according to claim 16, wherein: the irradiation step is a step of controlling the amount of impurities introduced to the surface of the solid substrate by changing at least one of the conditions of bias voltage, irradiation time, bias power, ion type, and sheath voltage with respect to the plasma irradiated to the surface of the solid substrate.

18. The method of introducing an impurity according to claim 16, wherein: the plasma is a gas-based plasma containing at least one selected from a rare gas, hydrogen, and a halogen.

19. The method of introducing an impurity according to claim 16, wherein: the method further includes an annealing step after the impurity introduction step, wherein the annealing step activates the impurity.

20. An impurity introducing apparatus includes: 1 st device for forming an amorphous layer on the surface of a solid substrate; a 2 nd device for introducing desired particles into the surface of the solid substrate; and a 3 rd means for annealing for activating the introduced desired particles; which can sequentially or simultaneously perform the formation of an amorphous layer on the surface of the solid substrate and the introduction of desired particles into the amorphous layer.

21. The impurity introducing apparatus according to claim 20, wherein: combining or integrating 2 or more devices selected from the 1 st device, the 2 nd device and the 3 rd device.