CN116203531A - Laser radar scanning and transmitting device and preparation method thereof - Google Patents

Abstract

The disclosure provides a laser radar scanning and transmitting device and a preparation method thereof. The laser radar scanning and transmitting device comprises: the device comprises a substrate and a plurality of vertical cavity surface emitting lasers, wherein the plurality of vertical cavity surface emitting lasers are arranged on the substrate in an array manner; wherein a plurality of grooves recessed downward and arranged at uniform intervals are formed on the top emission surface of each vertical cavity surface emitting laser, and at least one of the period, duty ratio, and depth of the grooves on each vertical cavity surface emitting laser is different from each other so that the emission angles of the laser beams emitted from each vertical cavity surface emitting laser are different.

Description

Laser radar scanning emission device and preparation method thereof

technical field

The disclosure relates to the technical field of photon and optoelectronic device design, in particular to a laser radar scanning emission device and a preparation method thereof.

Background technique

Lidar is a radar that works in the optical frequency band. Similar to the working principle of microwave radar, it uses electromagnetic waves in the optical frequency band to first transmit detection signals to the target, and then compares the received signals of the same band with the transmitted signals to obtain the target's position (distance, azimuth and height), Motion status (speed, attitude) and other information to realize the detection, tracking and identification of aircraft, missiles and other targets.

Near-infrared lidar has the characteristics of high resolution, human eye safety, strong penetrating power, easy integration, all-solid-state and all-solid-state and fast scanning speed. It is used in unmanned driving, robots, drones, smart education, and smart medical It has extremely important application prospects in civil fields such as digital cities and so on. At the same time, it has important national defense applications in precision guidance, hidden object reconnaissance, route guidance and target targeting.

The spatial scanning method of lidar can be divided into non-scanning system and scanning system. The scanning system can choose mechanical scanning, electrical scanning and binary optical scanning. The non-scanning imaging system uses multi-element detectors, which have a longer working distance. The detection system is different from the unit detection of scanning imaging, which can reduce the volume and weight of the equipment. At present, the scanning working system is mostly used.

Semiconductor diode lasers have become the preferred light source for small lidars due to their small size, light weight, robustness, high repetition rate, and potential low cost, as well as the availability of uncooled high-sensitivity avalanche photodiode (APD) detectors.

Common solid-state laser radars generally include phased array laser radars and Flash laser radars based on pixel-level time-of-flight measurement of electrically coupled devices (CCD).

Phased array lidar controls the emission angle of the laser beam by adjusting the phase of the beam and the wavelength of the laser to realize the scanning of the laser beam. Because it needs to couple the beam of the laser into the antenna array, and the beam entering the antenna array needs to be Beam splitting, the transmitting power of the antenna is much lower than the power of the laser light source, so its utilization rate of light is very low.

Flash lidar is to expand a laser beam, emit a laser covering a large area, and receive imaging through a high-sensitivity area array detector, which also makes it unable to perform long-distance detection.

Contents of the invention

In order to solve the technical problems in the prior art, the present disclosure provides a laser radar scanning emission device and its manufacturing method. The laser emission directions of each vertical cavity surface emitting laser are different, and each vertical cavity surface emitting laser is suitable for a certain angle The measurement improves the utilization rate of the light source.

An aspect of the embodiments of the present disclosure provides a laser radar scanning emission device, including: a substrate and a plurality of vertical cavity surface emitting lasers, and an array of multiple vertical cavity surface emitting lasers is arranged on the substrate. Wherein, the top emitting surface of each vertical cavity surface emitting laser is formed with a plurality of grooves that are depressed downwards and arranged at uniform intervals, and the period of the grooves on each of the vertical cavity surface emitting lasers, occupying At least one of the space ratio and the depth is different from each other, so that the exit angles of the laser beams emitted from the respective VCSELs are different.

According to an embodiment of the present disclosure, each VCSEL includes: a lower metal layer, a light emitting component, an upper contact layer, and an upper metal layer. A lower metal layer is disposed on one side of the substrate. The light emitting component is disposed on the other side of the substrate opposite to the lower metal layer, and is configured to emit laser light. The upper contact layer is disposed on the light emitting component. An upper metal layer is disposed on the upper contact layer, the upper metal layer cooperates with the lower metal layer to inject current into the light-emitting component, and the groove is formed on the upper contact layer.

According to an embodiment of the present disclosure, a transparent insulating layer is disposed on the sidewall of each vertical cavity surface emitting laser, and the upper metal layer includes: a first metal layer and a second metal layer. The first metal layer is configured as an ohmic contact layer electrically connected to the upper contact layer. The second metal layer covers the first metal layer and the transparent insulating layer on the sidewall of the vertical cavity surface emitting laser, and the second metal layer of adjacent vertical cavity surface emitting lasers is electrically isolated.

According to an embodiment of the present disclosure, the light emitting component includes: a lower Bragg reflector, a transition layer, an active layer and an upper Bragg reflector. The lower Bragg reflector is disposed on the other side of the substrate opposite to the lower metal layer, and forms a plurality of ridge strips. The transition layer is arranged on the lower Bragg reflector. An active layer is disposed on the transition layer, and the active layer is used for providing gain to generate laser light. An upper Bragg reflector is disposed on the active layer, the upper Bragg reflector cooperates with the lower Bragg reflector to form laser oscillation by reflecting laser light in the active layer, the upper contact layer is disposed on the upper on the Bragg mirror.

According to an embodiment of the present disclosure, the lidar scanning emission device further includes: a primary carrier board, a heat sink, and a plurality of wires. A primary carrier is disposed on a side of the lower metal layer opposite to the substrate, and the primary carrier is electrically connected to the lower metal layer. A heat sink is disposed on a side of the primary carrier plate opposite to the lower metal layer, and the heat sink is suitable for heat dissipation. A plurality of wires are suitable for electrically connecting the upper metal layer with the carrier pins of the primary carrier, so as to respectively inject current into each of the vertical cavity surface emitting lasers through an external power supply.

According to an embodiment of the present disclosure, the laser radar scanning transmitting device further includes: a circuit board. The circuit board includes a plurality of electric control switches controlled by the shift register, and a plurality of circuit pins connected by the control control of the electric control switches. Wherein, the circuit pins are electrically connected to the pins of the carrier board through a plurality of wires, and the external power supply supplies power to the plurality of vertical cavity surface emitting lasers respectively through the wires by controlling the electronically controlled switch.

According to an embodiment of the present disclosure, each of the vertical cavity surface emitting lasers is formed as a cuboid structure, with a length ranging from 100-3000 microns, a width ranging from 3-100 microns, and a height ranging from 2-10 microns. The distribution period ranges from 1 micron to 30 microns.

Another aspect of the present disclosure provides a method for preparing the above laser radar scanning emission device, including:

The light-emitting component and the upper contact layer are grown on the substrate as an epitaxial wafer.

The epitaxial wafer is etched to obtain a plurality of ridge structures isolated from each other.

Etching a plurality of grooves downward at uniform intervals along the height direction of each of the ridge structures, wherein at least one of the period, duty cycle and depth of the grooves on each of the ridge structures different from each other.

An upper metal layer is formed on the top of each ridge structure, and the upper metal layer forms a light outlet above the groove.

A lower metal layer is formed on the bottom of the substrate to obtain a plurality of vertical cavity surface emitting lasers.

According to an embodiment of the present disclosure, an upper metal layer is formed on the top of each ridge structure, and the step of forming a light outlet on the upper metal layer includes:

A first metal layer is formed on the top of each ridge structure, and a first light outlet is formed on the first metal layer,

forming a transparent insulating layer on the sidewall of each of the ridge structures, and

A second metal layer is formed on the top of the first metal layer and on the transparent insulating layer located on the sidewall of the ridge structure, and a second metal layer matching the first light outlet is formed on the second metal layer. The second light outlet is electrically isolated from the second metal layer of the adjacent vertical cavity surface emitting laser.

According to an embodiment of the present disclosure, the step of forming a transparent insulating layer on the sidewall of each of the ridge structures includes:

covering the sidewalls of the ridge structure and the first metal layer with a first transparent insulating layer,

removing the first transparent insulating layer on the sidewall of the ridge structure,

performing an oxidation process on the ridge structure,

again covering the sidewalls of the ridge structure and the first transparent insulating layer on the first metal layer with a second transparent insulating layer, and

The first transparent insulating layer and the second transparent insulating layer above the first metal layer are removed.

According to an embodiment of the present disclosure, the lidar scanning emission device provided by the present disclosure includes multiple vertical cavity surface emitting lasers arranged in an array, and each vertical cavity surface emitting laser forms the same angle symmetrical to the normal line of the array plane Two laser beams with low divergence angle. In each vertical-cavity surface-emitting laser, by adjusting the distribution and size of the grooves, the emitted laser beams can be emitted according to specific angles, which can be used to scan the laser beams of objects within a certain distance, and realize position determination through object reflection . Each vertical cavity surface emitting laser is suitable for the measurement of a certain angle, and does not require a complicated optical path, which increases the utilization rate of the light source.

Description of drawings

FIG. 1 schematically shows a perspective view of a lidar scanning transmitter device according to an embodiment of the present disclosure;

Fig. 2 is a cross-sectional view along the length direction of the vertical cavity surface emitting laser part of the laser radar scanning transmitting device shown in Fig. 1;

FIG. 3 schematically shows a flow chart of a manufacturing method of a lidar scanning emission device according to an embodiment of the present disclosure; and

4a-4k schematically illustrate a flow chart of manufacturing a lidar scanning emission device according to disclosed embodiments.

Explanation of reference signs:

1 - Substrate;

2- Lower Bragg reflector;

3 - Transition layer;

4 - active layer;

5- Upper Bragg reflector;

6 - contact layer;

7- Upper metal layer;

71 - first metal layer;

72 - second metal layer;

8 - lower metal layer;

9 - groove;

10-the first transparent insulating layer;

11 - the second transparent insulating layer;

12- primary carrier board;

121-carrier board pin;

13 - heat sink; and

14 - wire;

15 - Isolation tank.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. However, this disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity, and like reference numerals designate like elements throughout.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be understood, however, that these descriptions are exemplary only, and are not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the present disclosure. The terms "comprising", "comprising", etc. used herein indicate the presence of stated features, steps, operations and/or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

All terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification, and not be interpreted in an idealized or overly rigid manner.

In order to facilitate those skilled in the art to understand the technical solution of the present disclosure, the following technical terms are now explained.

Where expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted as those skilled in the art would normally understand the expression (for example, "having A, B, and C A system of at least one of "shall include, but not be limited to, systems with A alone, B alone, C alone, A and B, A and C, B and C, and/or A, B, C, etc. ). Where expressions such as "at least one of A, B, or C, etc." are used, they should generally be interpreted as those skilled in the art would normally understand the expression (for example, "having A, B, or C A system of at least one of "shall include, but not be limited to, systems with A alone, B alone, C alone, A and B, A and C, B and C, and/or A, B, C, etc. ).

Fig. 1 schematically shows a perspective view of a laser radar scanning transmitting device according to an embodiment of the present disclosure, and Fig. 2 is a cross-sectional view along the length direction of the vertical cavity surface emitting laser part of the laser radar scanning transmitting device shown in Fig. 1 .

An aspect of the embodiments of the present disclosure provides a laser radar scanning emission device, as shown in Figure 1 and Figure 2, including: a substrate 1 and a plurality of vertical cavity surface emitting lasers, a plurality of vertical cavity surface emitting laser array rows The cloth is provided on the substrate 1 . Wherein, the top emitting surface of each vertical cavity surface emitting laser is formed with a plurality of grooves 9 that are recessed downwards and arranged at uniform intervals, and the period, duty cycle and depth of the grooves 9 on each vertical cavity surface emitting laser At least one of them is different from each other, so that the exit angles of the laser beams emitted from the respective VCSELs are different.

As shown in FIG. 2, L represents the normal to the array plane of the vertical cavity surface emitting laser, and L1 and L2 respectively represent two low-divergence beams emitted by the vertical cavity surface emitting laser according to the embodiment of the present disclosure, which are symmetrical with respect to the normal of the array plane. θ is the angle between the laser beam emitted by the vertical cavity surface emitting laser and the normal of the array plane.

According to an embodiment of the present disclosure, the lidar scanning emission device provided by the present disclosure includes multiple vertical cavity surface emitting lasers arranged in an array, and the top surfaces of the multiple vertical cavity surface emitting lasers are respectively set with period, duty cycle and The grooves differ in at least one of their depths. In this way, a grating-like structure is formed on the exit surface of each laser, so that the laser beams emitted by the lasers form interference and diffraction. The laser beam is strengthened in a certain direction, or weakened in a certain direction, so as to form two low-divergence laser beams with an angle θ symmetrical to the normal of the array plane, so that the laser beam can be emitted at a specific angle. By adjusting at least one of the period, duty cycle and depth of the grooves on each vertical cavity surface emitting laser, the exit angle θ of the laser beam is controlled from 0 degrees to 85 degrees, so that the laser beam emitted by each laser Launched at a specific angle, it can be used to scan objects within a certain distance, and the position can be determined by the reflection of the object. Each vertical cavity surface emitting laser only needs to be responsible for the measurement of a certain angle, and does not require complicated optical paths, which increases the utilization rate of the light source. Moreover, the scanning range of the laser beam generated by the laser radar scanning emitting device provided in the present disclosure can realize a scanning range of 0 degrees to 170 degrees according to the size of the array. Compared with silicon-based phased array radar and Flash lidar, it can achieve higher power output. Compared with the mechanical lidar, the present disclosure can achieve high power output while reducing the volume of the lidar and improving its integration, which can be more widely implemented in autonomous driving, drones, robots and other artificial intelligence field applications.

Those skilled in the art understand that a Vertical-Cavity Surface-Emitting Laser (Vertical-Cavity Surface-Emitting Laser, referred to as VCSEL, also known as a Vertical-Cavity Surface-Emitting Laser) is a semiconductor laser whose laser light is emitted perpendicular to the top surface.

According to an embodiment of the present disclosure, the arrangement of the multi-channel vertical cavity surface emitting lasers on the substrate 1 may include any one of single row, single row or multiple rows and multiple rows.

According to an embodiment of the present disclosure, the material of the substrate 1 is N-type or P-type GaAs.

According to an embodiment of the present disclosure, the thickness range of the substrate 1 includes 80-200 microns, for example, any of 80 microns, 100 microns, 110 microns, 125 microns, 130 microns, 150 microns, 180 microns, 200 microns, etc. kind.

In an exemplary embodiment, the thickness of the substrate 1 is 145 microns.

In an exemplary embodiment, the distribution periods of the grooves 9 on each vertical cavity surface emitting laser are different.

In an exemplary embodiment, the duty cycle and depth of the grooves 9 on each VCSEL are different.

In an exemplary embodiment, the period, duty cycle and depth of the grooves 9 on each VCSEL are different.

According to an embodiment of the present disclosure, the distribution period of the grooves 9 ranges from 1 micron to 30 microns, such as any one of 1 micron, 5 microns, 10 microns, 15 microns, 20 microns, 25 microns, 30 microns, etc. .

According to an embodiment of the present disclosure, the groove 9 has a width ranging from 5 microns to 30 microns, such as any one of 5 microns, 10 microns, 15 microns, 20 microns, 25 microns, and 30 microns.

According to an embodiment of the present disclosure, the length range of the groove 9 is smaller than the width of the VCSEL.

According to an embodiment of the present disclosure, as shown in FIG. 2 , each VCSEL includes: a lower metal layer 8 , a light emitting component, an upper contact layer 6 and an upper metal layer 7 . The lower metal layer 8 is disposed on one side of the substrate 1 . The light emitting component is disposed on the other side of the substrate 1 opposite to the lower metal layer 8 and configured to emit laser light. The upper contact layer 6 is disposed on the light emitting component. The upper metal layer 7 is disposed on the upper contact layer 6 , the upper metal layer 7 cooperates with the lower metal layer 8 to inject current into the light-emitting component, and the groove 9 is formed on the upper contact layer 6 .

According to an embodiment of the present disclosure, the material of the upper contact layer 6 is AlGaAs or GaAs.

According to an embodiment of the present disclosure, the material of the lower metal layer 8 includes any one of gold-germanium-nickel-gold alloy, indium, gold-tin alloy, and the like.

According to an embodiment of the present disclosure, a transparent insulating layer is provided on the sidewall of each VCSEL, that is, the second transparent insulating layer 11 described below, and the upper metal layer 7 includes: a first metal layer 71 and a second metal layer 71 Two metal layers 72 . The first metal layer 71 is provided as an ohmic contact layer electrically connected to the upper contact layer 6 . The second metal layer 72 covers the first metal layer 71 and the second transparent insulating layer 11 located on the sidewall of the VCSEL, and the second metal layer 72 of adjacent VCSELs is electrically isolated.

According to an embodiment of the present disclosure, the material of the second transparent insulating layer 11 is silicon dioxide or silicon nitride.

According to an embodiment of the present disclosure, the function of the first metal layer 71 is to form a good ohmic contact between the second metal layer 72 and the upper contact layer 6 .

According to an embodiment of the present disclosure, as shown in FIG. 2 , the light emitting component includes: a lower Bragg reflector 2 , a transition layer 3 , an active layer 4 and an upper Bragg reflector 5 . The lower Bragg reflector 2 is disposed on the other side of the substrate 1 opposite to the lower metal layer 8 and forms a plurality of ridge strips. The transition layer 3 is arranged on the lower Bragg reflector 2 . The active layer 4 is disposed on the transition layer 3 , and the active layer 4 is used to provide gain to generate laser light when the upper metal layer 7 and the lower metal layer 8 provide injection current. The upper Bragg reflector 5 is arranged on the active layer 4, the upper Bragg reflector 5 cooperates with the lower Bragg reflector 2 to form laser oscillation by reflecting the laser in the active layer 4, and the upper contact layer 6 is arranged on the upper Bragg reflector 5 superior.

In an exemplary embodiment, the material of the lower Bragg reflector 2 is AlGaAs.

In an exemplary embodiment, the material of the transition layer 3 is AlGaAs.

In an exemplary embodiment, the material of the active layer 4 is InGaAs/GaAs quantum wells or quantum dots.

In an exemplary embodiment, the material of the upper Bragg reflector 5 is AlGaAs.

According to an embodiment of the present disclosure, the depth of the groove 9 (the distance between the top surface of the contact layer 6 and the bottom surface of the bottom of the groove 9) is smaller than the distance between the top surface of the contact layer 6 and the bottom surface of the upper Bragg reflector 5. distance.

According to the embodiment of the present disclosure, there is an inversion of the number of particles in the active layer 4, so that the gain provided by the laser coal is sufficient to exceed the loss. When the upper metal layer 7 and the lower metal layer 8 are injected with current, the light intensity will be Continuously increasing, when the electrons in the high-energy state and low conduction band transition to the low-energy state valence band, as the light of a specific wavelength is reflected back and forth on the upper and lower mirrors of the active layer 4, the amplification process is repeated to form laser light.

According to the embodiment of the present disclosure, the active layer 4 is sandwiched between the upper Bragg reflector and the lower Bragg reflector. When the vertical cavity surface emitting laser is working, a standing wave will be formed in the active region, so that photon energy is amplified and finally lasing is formed.

According to an embodiment of the present disclosure, the refractive index of the upper Bragg reflector 5 is smaller than that of the lower Bragg reflector 2, so that a part of the light is emitted.

According to an embodiment of the present disclosure, both sides of the active layer 4 may also include confinement layers. The confinement layers can confine carriers on the one hand, and on the other hand, can adjust the length of the resonant cavity so that the resonant wavelength is exactly the required laser wavelength of the laser.

According to an embodiment of the present disclosure, as shown in FIG. 1 , the lidar scanning and transmitting device further includes: a primary carrier 12 , a heat sink 13 and a plurality of wires 14 . The primary carrier 12 is disposed on the side of the lower metal layer 8 opposite to the substrate 1 , and the primary carrier 12 is electrically connected to the lower metal layer 8 . The heat sink 13 is disposed on the side of the primary carrier 12 opposite to the lower metal layer 8 , and the heat sink 13 is suitable for heat dissipation. A plurality of wires 14 are suitable for electrically connecting the upper metal layer 7 with the carrier pins 121 of the primary carrier 12, so as to respectively inject current into each VCSEL through an external power source.

According to an embodiment of the present disclosure, the material of the wire 14 includes metal materials such as copper, iron, gold, silver, and alloys.

In an exemplary embodiment, the wire 14 is a gold wire.

According to an embodiment of the present disclosure, the material of the heat sink 13 includes any one of aluminum nitride ceramic plates, oxygen-free copper, and tungsten steel.

According to an embodiment of the present disclosure, the material of the primary plate 11 includes any one of aluminum nitride, sapphire, and a silicon wafer with a silicon dioxide layer grown on its surface.

According to an embodiment of the present disclosure, the primary carrier 12 is used to carry multiple vertical cavity surface emitting lasers, and the interior of the primary carrier 12 is wired to conduct the connection between the lower metal layer 8, the upper metal layer 7 and the circuit board. In addition to the function of carrying signals, the primary carrier board 12 also has additional functions such as protection circuits, wires 14, design of heat dissipation channels, and establishment of modular standards for components.

According to an embodiment of the present disclosure, the laser radar scanning transmitting device further includes: a circuit board. The circuit board includes a plurality of electronically controlled switches controlled by the shift register, and a plurality of circuit pins connected by the electrically controlled switches. Wherein, the circuit pins are electrically connected to the carrier board pins 121 through a plurality of wires 14 , and the external power supply respectively supplies power to a plurality of vertical cavity surface emitting lasers through the wires 14 by controlling the electronically controlled switch.

According to an embodiment of the present disclosure, the circuit board is connected to an external power supply to realize scanning control driving, which is mainly manifested in that each vertical cavity surface emitting laser is respectively connected to the primary carrier board and the pins on the circuit board through wires. These pins are connected to the electrical control switches on the circuit board, and all the electrical control switches are connected to the output terminals of the laser current source module. When working, the laser current source module is always on, and each electrical switch connected to each channel of vertical cavity surface emitting lasers is controlled by a shift register, so as to individually turn on each channel of vertical cavity surface emitting lasers.

According to an embodiment of the present disclosure, as shown in FIG. 1 , each VCSEL is formed as a cuboid structure, with a length ranging from 100-3000 microns, a width ranging from 3-100 microns, and a height ranging from 2-10 microns.

According to an embodiment of the present disclosure, each VCSEL may also be formed in a rectangular-like structure, such as a trapezoidal structure.

In an exemplary embodiment, each VCSEL is formed as a cuboid structure with a length of 1000 microns, a width of 50 microns and a height of 5 microns.

In an exemplary embodiment, each VCSEL is formed as a cuboid structure with a length of 100 microns, a width of 3 microns, and a height of 2 microns.

In an exemplary embodiment, each VCSEL is formed as a cuboid structure with a length of 3000 microns, a width of 100 microns and a height of 8 microns.

In an exemplary embodiment, each VCSEL is formed as a cuboid structure with a length of 2000 microns, a width of 80 microns, and a height of 3 microns.

Fig. 3 schematically shows a flow chart of a method for manufacturing a lidar scanning emission device according to an embodiment of the present disclosure.

Another aspect of the present disclosure provides a method for preparing the above-mentioned laser radar scanning emission device, as shown in FIG. 3 , including operation S310-operation S350:

Operation S310: Referring to FIG. 4a, grow a light emitting component and an upper contact layer 6 on the substrate 1 as an epitaxial wafer. The light emitting component includes a lower Bragg reflector 2 , a transition layer 3 , an active layer 4 and an upper Bragg reflector 5 .

Operation S320: referring to FIG. 4b, etching the epitaxial wafer to obtain a plurality of ridge structures isolated from each other.

Operation S330: Referring to FIG. 4c, a plurality of grooves 9 are etched downward at uniform intervals along the height direction of each ridge structure, wherein the period, duty cycle and depth of the grooves 9 on each ridge structure are At least one of them is different from each other.

Operation S340: forming an upper metal layer 7 on top of each ridge structure, and the upper metal layer 7 forms a light exit above the groove 9 .

Operation S350: forming a lower metal layer 8 on the bottom of the substrate 1 to obtain a laser radar scanning transmitter device composed of a plurality of vertical cavity surface emitting lasers.

According to an embodiment of the present disclosure, the length of the light exit port ranges from 100 microns to 2000 microns.

In an exemplary embodiment, the length of the light outlet is any one of 100 microns, 500 microns, 1000 microns, 1500 microns, 1700 microns, 2000 microns and the like.

According to an embodiment of the present disclosure, the area on the top of the vertical cavity surface emitting laser not covered by the metal layer is the light outlet.

According to an embodiment of the present disclosure, the epitaxial wafer is grown in a vapor phase epitaxy (MOCVD) or molecular beam epitaxy (MBE) growth method.

According to an embodiment of the present disclosure, operation S340: forming an upper metal layer 7 on the top of each ridge structure, and the step of forming a light outlet on the upper metal layer 7 includes:

Referring to FIG. 4 d , a first metal layer 71 is formed on the top of each ridge structure, and a first light outlet is formed on the first metal layer 71 .

A transparent insulating layer is formed on the sidewall of each ridge structure.

A second metal layer 72 is formed on the top of the first metal layer 71 and on the transparent insulating layer positioned on the sidewall of the ridge structure, and a second light outlet matching with the first light outlet is formed on the second metal layer 72. The second metal layer 72 is electrically isolated adjacent to the VCSEL.

According to an embodiment of the present disclosure, the method of forming the first light outlet on the first metal layer 71 is any one or more of methods such as photolithography, etching, and lift-off.

According to an embodiment of the present disclosure, the step of forming the second transparent insulating layer 11 on the sidewall of each ridge structure includes:

Referring to FIG. 4 e , the first transparent insulating layer 10 covers the sidewalls of the ridge structure and the first metal layer 71 .

Referring to FIG. 4f, the first transparent insulating layer 10 on the sidewall of the ridge structure is removed.

An oxidation process is performed on the ridge structure.

Referring to FIG. 4 g , the second transparent insulating layer 11 is again covered on the sidewalls of the ridge structure and the first transparent insulating layer 10 on the first metal layer 71 .

Referring to FIG. 4h, the first transparent insulating layer 10 and the second transparent insulating layer 11 above the first metal layer 71 are removed.

According to an embodiment of the present disclosure, the first transparent insulating layer 10 is suitable for preventing the groove 9 structure from being oxidized during the oxidation process.

According to an embodiment of the present disclosure, the material of the first transparent insulating layer 10 is silicon dioxide or silicon nitride.

According to an embodiment of the present disclosure, the purpose of performing an oxidation process on the polar structure is to limit the injection current of the VCSEL and reduce the lasing current.

Figures 4a-k schematically illustrate a flow chart of fabrication of a lidar scanning emission device according to disclosed embodiments.

In an exemplary embodiment, a method for preparing the above-mentioned laser radar scanning emission device includes:

As shown in FIG. 4 a , a lower Bragg reflector 2 , a transition layer 3 , an active region, an upper Bragg reflector 5 and an upper contact layer 6 are formed on a substrate 1 as an epitaxial wafer.

The epitaxial wafer is dry etched to the lower Bragg reflector 2, so that four ridge strips are formed on the lower Bragg reflector 2, as shown in FIG. 4b, and four ridge structures isolated from each other are obtained.

A plurality of grooves 9 are etched downward at uniform intervals along the height direction of each ridge structure, wherein the depths of the grooves 9 on each ridge structure are different from each other. As shown in Figure 4c, from left to right are the first to fourth ridge structures, wherein the depth of the groove 9 of the third ridge structure>the depth of the groove 9 of the fourth shape structure>the depth of the groove 9 of the second shape structure The depth of the groove 9 > the depth of the groove 9 of the first shape structure.

As shown in FIG. 4 d , a first metal layer 71 is formed on the top of each ridge structure, and a first light outlet is formed on the first metal layer 71 .

As shown in FIG. 4 e , the first transparent insulating layer 10 covers the sidewalls of the ridge structure and the first metal layer 71 .

As shown in FIG. 4f, the first transparent insulating layer 10 on the sidewall of the ridge structure is removed, and an oxidation process is performed on the ridge structure.

As shown in FIG. 4 g , the second transparent insulating layer 11 is again covered on the sidewalls of the ridge structure and the first transparent insulating layer 10 on the first metal layer 71 .

As shown in FIG. 4h , the first transparent insulating layer 10 and the second transparent insulating layer 11 above the first metal layer 71 are removed.

As shown in FIG. 4i, a second metal layer 72 is formed on the top of the first metal layer 71 and on the transparent insulating layer located on the sidewall of the ridge structure. Second light outlet.

As shown in FIG. 4 j , isolation grooves 15 are formed between the second metal layers 72 of adjacent vertical cavity surface emitting lasers to isolate each vertical cavity surface emitting laser so that current can be injected separately.

In order to facilitate the subsequent cleavage and the heat conduction of each VCSEL, the substrate 1 is thinned so that the thickness of the substrate 1 is 135 microns. As shown in FIG. 4k , a lower metal layer 8 is formed on the bottom of the thinned substrate 1 to form a 4-way vertical cavity surface emitting laser structure arranged in an array.

The 4-way vertical cavity surface-emitting laser structure set in the array is subjected to high temperature (400°C-420°C) for alloying under a mixed gas of nitrogen and hydrogen, and then cleaved to obtain an array chip.

The array chips are fixed on the primary carrier with thermally conductive glue, and the upper metal layer 7 is connected to the carrier pins 121 of the primary carrier with wires 14 .

The primary plate is sintered onto the heat sink 13 .

The heat sink 13 is fixed to the circuit board with heat-conducting glue, and the carrier board pins 121 on the primary carrier plate 11 are connected to the circuit pins on the circuit board through wires 14 to complete the preparation of the final laser radar emitting device.

In another exemplary embodiment, a preparation method of the above-mentioned laser radar scanning emission device includes:

A lower Bragg reflector 2, a transition layer 3, an active region, an upper Bragg reflector 5 and an upper contact layer 6 are formed on a substrate 1 as an epitaxial wafer.

A first metal layer 71 is grown on the top of the epitaxial wafer, and a light-emitting window is reserved.

A groove 9 is etched on the top of the ridge laser in the reserved light emitting window, and the period and depth of the groove 9 in different light emitting windows are different.

A first transparent insulating layer 10 is grown on the top of the ridge laser, wherein the material of the first transparent insulating layer 10 is silicon nitride.

By dry etching to the lower Bragg reflector 2, a multi-channel ridge-shaped stripe laser structure is obtained.

An oxidation process is performed on the ridge stripe laser structure to reduce the lasing current of the laser.

Covering the second transparent insulating layer 11 again, wherein the material of the second transparent insulating layer 11 is silicon nitride.

Remove the first transparent insulating layer 10 and the second transparent insulating layer 11 above the first metal layer 71 , cover the second metal layer 72 , make the second metal layer 72 contact with the first metal layer 71 to form the upper metal layer 7 .

On the upper metal layer 7, a window is opened by photolithography and etching, and an isolation groove is formed to isolate each vertical cavity surface emitting laser, so that it can inject current independently.

The substrate 1 is thinned to a thickness ranging from 100 microns to 150 microns, and a lower metal layer 8 is grown on the bottom of the substrate 1 to form a multi-channel vertical cavity surface emitting laser structure arranged in an array.

For the multi-channel vertical cavity surface emitting laser structure set up in the array, under the mixed gas of nitrogen and hydrogen, apply high temperature (400 degrees Celsius to 420 degrees Celsius) for alloying, and then divide the obtained laser chips into array device dies, that is, decompose After processing, an array chip is obtained.

The array chip, the primary carrier 12 and the circuit board are sequentially fixed by heat-conducting glue, and the upper metal layer 7, the primary carrier 12 and the pins on the circuit board are sequentially connected by gold wires on the automatic wire bonding machine to complete the final laser radar launch. Preparation of the device.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that, in the accompanying drawings or in the text of the specification, implementations that are not shown or described are forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can easily modify or replace them.

According to the above description, those skilled in the art should have a clear understanding of the lidar scanning emission device provided by the present disclosure.

To sum up, the present disclosure provides a laser radar scanning emission device based on a vertical cavity surface emitting laser array, which realizes the use of lower-cost laser radar scanning in the fields of automatic driving, drones, robots and other artificial intelligence.

It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only referring to the directions of the drawings, not Used to limit the protection scope of this disclosure. Throughout the drawings, the same elements are indicated by the same or similar reference numerals. Where it may cause confusion in the understanding of the present disclosure, conventional structures or configurations will be omitted, and the shapes and sizes of components in the drawings do not reflect real sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure.

Unless known to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties obtained from the teachings of the present disclosure. Specifically, all numbers used in the specification and claims to indicate the content of components, reaction conditions, etc., should be understood to be modified by the term "about" in all cases. In general, the expressed meaning is meant to include a variation of ±10% in some embodiments, a variation of ±5% in some embodiments, a variation of ±1% in some embodiments, a variation of ±1% in some embodiments, and a variation of ±1% in some embodiments ±0.5% variation in the example.

Words such as "first", "second", "third" and the like used in the description and claims to modify the corresponding elements do not in themselves mean that the elements have any ordinal numbers, nor The use of these ordinal numbers to represent the sequence of an element with respect to another element, or the order of manufacturing methods, is only used to clearly distinguish one element with a certain designation from another element with the same designation.

In addition, unless specifically described or steps that must occur sequentially, the order of the above steps is not limited to that listed above and may be changed or rearranged according to the desired design. Moreover, the above-mentioned embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, technical features in different embodiments can be freely combined to form more embodiments.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above descriptions are only specific embodiments of the present disclosure, and are not intended to limit the present disclosure. Within the spirit and principles of the present disclosure, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present disclosure.

Claims (10)

1. A laser radar scanning transmitter, comprising: Substrate(1); A plurality of vertical cavity surface emitting lasers arranged in an array on the substrate (1); Wherein, a plurality of grooves (9) concave downwards and arranged at uniform intervals are formed on the top emitting surface of each of the vertical cavity surface emitting lasers, and the grooves (9) on each of the vertical cavity surface emitting lasers are At least one of period, duty cycle and depth is different from each other, so that the exit angles of the laser beams emitted from the respective VCSELs are different. 2. The lidar scanning emission device according to claim 1, wherein each vertical cavity surface emitting laser comprises: a lower metal layer (8), arranged on one side of the substrate (1); a light emitting component, disposed on the other side of the substrate (1) opposite to the lower metal layer (8), and configured to emit laser light; an upper contact layer (6), disposed on the light-emitting component; and an upper metal layer (7), arranged on the upper contact layer (6), the upper metal layer (7) cooperates with the lower metal layer (8) to inject current into the light-emitting component, the groove (9) formed on said upper contact layer (6). 3. The lidar scanning emission device according to claim 2, wherein a transparent insulating layer is arranged on the sidewall of each said vertical cavity surface emitting laser, and The upper metal layer (7) includes: A first metal layer (71), arranged as an ohmic contact layer electrically connected to the upper contact layer (6); and The second metal layer (72), covered on the first metal layer (71) and the transparent insulating layer on the side wall of the vertical cavity surface emitting laser, the second metal adjacent to the vertical cavity surface emitting laser Layer (72) is electrically isolated. 4. The lidar scanning emission device according to claim 2 or 3, wherein the light-emitting component comprises: a lower Bragg reflector (2), arranged on the other side of the substrate (1) opposite to the lower metal layer (8), and forming a plurality of ridge strips; a transition layer (3), arranged on the lower Bragg reflector (2); An active layer (4), arranged on the transition layer (3), the active layer (4) is used to provide gain to generate laser light; an upper Bragg reflector (5), arranged on the active layer (4), and the upper Bragg reflector (2) cooperates with the lower Bragg reflector (5) to pass reflection in the active layer (4) The laser light forms laser oscillation, and the upper contact layer (6) is arranged on the upper Bragg reflector (5). 5. The lidar scanning emission device according to claim 1, further comprising: A primary carrier (12), arranged on the side of the lower metal layer (8) opposite to the substrate (1), the primary carrier (12) is electrically connected to the lower metal layer (8) ; A heat sink (13), arranged on the side of the primary carrier (12) opposite to the lower metal layer (8), the heat sink (13) is suitable for heat dissipation; A plurality of wires (14), suitable for electrically connecting the upper metal layer (7) with the carrier pins (121) of the primary carrier (12), so as to inject current into each of the primary carriers (12) through an external power supply Vertical cavity surface emitting laser. 6. The lidar scanning transmitter device according to claim 4, further comprising: A circuit board, including a plurality of electronically controlled switches controlled by a shift register, and a plurality of circuit pins connected by the electronically controlled switches; Wherein, the circuit pins are electrically connected to the carrier board pins (121) through a plurality of the wires (14), and the external power supply is respectively connected to the plurality of the vertical wires through the wires by controlling the electronically controlled switch. Cavity surface emitting laser power supply. 7. The lidar scanning emission device according to claim 1, each of the vertical cavity surface emitting lasers is formed into a cuboid structure, the length range includes 100-3000 microns, the width range includes 3-100 microns, and the height range includes 2- 10 microns, the distribution period of the grooves (9) ranges from 1 micron to 30 microns. 8. A preparation method for preparing the lidar scanning emission device described in any one of claims 1-7, comprising: growing the light-emitting component and the upper contact layer (6) on the substrate (1) as an epitaxial wafer; Etching the epitaxial wafer to obtain a plurality of ridge structures isolated from each other; Etching a plurality of grooves (9) downward at uniform intervals along the height direction of each of the ridge structures, wherein the period, duty cycle and At least one of the depths are different from each other; An upper metal layer (7) is formed on the top of each ridge structure, and the upper metal layer (7) forms a light outlet above the groove (9); A lower metal layer (8) is formed on the bottom of the substrate (1) to obtain a plurality of vertical cavity surface emitting lasers. 9. The method according to claim 8, wherein an upper metal layer (7) is formed at the top of each of the ridge structures, and the step of forming a light outlet on the upper metal layer (7) comprises: A first metal layer (71) is formed on the top of each of the ridge structures, and a first light outlet is formed on the first metal layer (71); forming a transparent insulating layer on the sidewall of each of the ridge structures; and A second metal layer (81) is formed on the top of the first metal layer (71) and on the transparent insulating layer located on the sidewall of the ridge structure, and the second metal layer (81) is formed on the second metal layer (81). The second light outlet matched with the first light outlet is electrically isolated from the second metal layer (81) of the adjacent vertical cavity surface emitting laser. 10. The method according to claim 9, wherein the step of forming a transparent insulating layer on the sidewall of each of the ridge structures comprises: Covering the first transparent insulating layer (10) on the side walls of the ridge structure and the first metal layer (71); removing the first transparent insulating layer (10) on the sidewall of the ridge structure; performing an oxidation process on the ridge structure; covering the sidewalls of the ridge structure and the first transparent insulating layer (10) on the first metal layer (71) again with a second transparent insulating layer (11); and The first transparent insulating layer (10) and the second transparent insulating layer (11) above the first metal layer (71) are removed.

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