High power semiconductor laser bar and single tube

Abstract

The application discloses a high-power semiconductor laser bar and a single tube, the high-power semiconductor laser bar comprising a first type of ohmic contact electrode, a first type of substrate and a plurality of laser units, the plurality of laser units being arranged along a first direction and being arranged on one side of the first type of substrate, the first type of ohmic contact electrode being arranged on the other side of the first type of substrate, the laser unit comprising an epitaxial layer, the epitaxial layer being arranged on one side of the first type of substrate and being located between two isolation grooves, a current injection area being arranged on a mesa of the epitaxial layer, two front narrow grooves and / or two rear narrow grooves being symmetrically arranged on two sides of the epitaxial layer, the two front narrow grooves being respectively communicated with the two isolation grooves, the two front narrow grooves being located between a front light-out surface of the laser unit and the current injection area, a minimum distance between the two front narrow grooves being less than a width of the current injection area, and the two rear narrow grooves being respectively communicated with the two isolation grooves. The application can improve the reliability of the bar and reduce the production cost of the bar.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a high-power semiconductor laser bar and single tube. Background Technology

[0002] LiDAR can acquire information such as the distance and speed of a target with high accuracy and precision, or achieve target imaging. It plays an important role in fields such as ranging, surveying, or navigation. High-power semiconductor lasers are the core components of LiDAR. In order to acquire targets at greater distances with higher precision, LiDAR requires the use of bars with higher power and smaller near-field spot size.

[0003] With increasing demands for measurement distance and accuracy, the power density of laser radar sensors is required to be higher, meaning that the near-field spot width must be smaller while the laser pulse power must be larger. Current methods typically reduce the near-field spot width by decreasing the overall width of the epitaxial layer and increase the laser pulse power by injecting a larger pulse current into the current injection region. However, since the current injection region is located on the epitaxial layer's mesa, reducing the overall width of the epitaxial layer inevitably reduces the width of the current injection region, resulting in a smaller area. On one hand, injecting a larger pulse current into a smaller current injection region increases the injected current density, thus reducing the sensor's reliability. On the other hand, a smaller current injection region makes wire bonding in the region more difficult, increasing the sensor's production cost. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a high-power semiconductor laser bar and single tube, which can improve the reliability of the bar and facilitate wire bonding in the current injection region, thereby reducing the production cost of the bar.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A first aspect of the present invention provides a high-power semiconductor laser bar, comprising a first type ohmic contact electrode, a first type substrate, and a plurality of laser units. The plurality of laser units are arranged along a first direction and disposed on one side of the first type substrate. The first type ohmic contact electrode is disposed on the other side of the first type substrate. Each laser unit includes an epitaxial layer disposed on one side of the first type substrate and located between two isolation trenches. A current injection region is provided on the mesa of the epitaxial layer. Two front narrowing trenches and / or two rear narrowing trenches are symmetrically arranged on both sides of the epitaxial layer. The two front narrowing trenches are respectively connected to the two isolation trenches. The two front narrowing trenches are located between the front emitting surface of the laser unit and the current injection region. The minimum distance between the two front narrowing trenches is less than the width of the current injection region. The two rear narrowing trenches are respectively connected to the two isolation trenches. The two rear narrowing trenches are located between the rear emitting surface of the laser unit and the current injection region. The minimum distance between the two rear narrowing trenches is less than the width of the current injection region.

[0007] As a preferred technical solution, two front narrowing slots are symmetrically arranged on both sides of the epitaxial layer; each front narrowing slot includes a front narrowing region, and the front narrowing regions of the two front narrowing slots are respectively connected to two isolation slots. The front narrowing region is located between the front light-emitting surface of the laser unit and the current injection region. The minimum distance between the front narrowing regions of the two front narrowing slots is less than the width of the current injection region. The cross-sectional shape of the front narrowing region is trapezoidal, triangular, or rectangular.

[0008] As a preferred technical solution, two front narrowing slots and two rear narrowing slots are symmetrically arranged on both sides of the epitaxial layer; the front narrowing slot includes two front narrowing regions, namely a first front narrowing region and a second front narrowing region, and the first front narrowing region and the second front narrowing region of the two front narrowing slots are respectively connected to two isolation slots. The first front narrowing region and the second front narrowing region are located between the front emitting surface of the laser unit and the current injection region, and the two are arranged alternately along the direction close to the front emitting surface of the laser unit. The minimum distance between the first front narrowing regions of the two front narrowing slots is equal to the distance between the front emitting surface of the laser unit and the current injection region. The widths of the current injection regions are equal, and the minimum distance between the second front narrowing regions of the two front narrowing slots is less than the width of the current injection region; the rear narrowing slot includes a rear narrowing region, and the rear narrowing regions of the two rear narrowing slots are respectively connected to the two isolation slots. The rear narrowing region is located between the rear light-emitting surface of the laser unit and the current injection region, and the minimum distance between the rear narrowing regions of the two rear narrowing slots is less than the width of the current injection region; the cross-sectional shapes of the first and second front narrowing regions are both trapezoidal, triangular, or rectangular, and the cross-sectional shape of the rear narrowing region is trapezoidal, triangular, or rectangular.

[0009] As a preferred technical solution, two back narrowing grooves are symmetrically arranged on both sides of the epitaxial layer; each back narrowing groove includes two back narrowing regions, namely a first back narrowing region and a second back narrowing region. The first and second back narrowing regions of the two back narrowing grooves are respectively connected to two isolation grooves. The first and second back narrowing regions are located between the rear emitting surface of the laser unit and the current injection region, and are arranged alternately along the direction close to the rear emitting surface of the laser unit. The minimum distance between the first back narrowing regions of the two back narrowing grooves is equal to the width of the current injection region, and the minimum distance between the second back narrowing regions of the two back narrowing grooves is less than the width of the current injection region. The cross-sectional shape of the first and second back narrowing regions is trapezoidal, triangular, or rectangular.

[0010] As a preferred technical solution, the isolation groove includes a middle area and two side end areas, which are respectively disposed at both ends of the middle area. One side end area is close to the front light-emitting surface of the laser unit, and the other side end area is close to the rear light-emitting surface of the laser unit.

[0011] As a preferred technical solution, two front narrowing grooves are symmetrically arranged on both sides of the epitaxial layer, and the two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode, the insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two front narrowing grooves, the middle area of ​​the two isolation grooves and the side end area of ​​the two isolation grooves, and the second type ohmic contact electrode covers the current injection area, the two front narrowing grooves and the middle area of ​​the two isolation grooves.

[0012] As a preferred technical solution, two front narrowing grooves are symmetrically arranged on both sides of the epitaxial layer, and the two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode, the insulating layer covers the area of ​​the epitaxial layer mesa except for the current injection region, both sides of the epitaxial layer, the bottom and sidewalls of the two front narrowing grooves, the bottom and sidewalls of the middle area of ​​the two isolation grooves, and the bottom and sidewalls of the side end areas of the two isolation grooves, and the second type ohmic contact electrode covers the current injection region.

[0013] As a preferred technical solution, two front narrowing grooves and two rear narrowing grooves are symmetrically arranged on both sides of the epitaxial layer. The two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves, and the two rear narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves. The laser unit also includes an insulating layer and a second type ohmic contact electrode. The insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two front narrowing grooves, the two rear narrowing grooves, the middle area of ​​the two isolation grooves, and the side end areas of the two isolation grooves. The second type ohmic contact electrode covers the current injection area, the two front narrowing grooves, the two rear narrowing grooves, and the middle area of ​​the two isolation grooves.

[0014] As a preferred technical solution, two back narrowing grooves are symmetrically arranged on both sides of the epitaxial layer, and the two back narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode, the insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two back narrowing grooves, the middle area of ​​the two isolation grooves and the side end area of ​​the two isolation grooves, and the second type ohmic contact electrode covers the current injection area, the two back narrowing grooves and the middle area of ​​the two isolation grooves.

[0015] As a preferred technical solution, the epitaxial layer includes a light-emitting unit disposed on one side of the first type substrate, and the surface of the light-emitting unit is provided with a second type ohmic contact layer. Alternatively, the epitaxial layer includes multiple light-emitting units, which are arranged sequentially from bottom to top at intervals, with adjacent light-emitting units connected in series through a tunnel junction. Among the multiple light-emitting units, the bottommost light-emitting unit is disposed on one side of the first type substrate, and the surface of the topmost light-emitting unit is provided with a second type ohmic contact layer. The surface of the second type ohmic contact layer forms the mesa of the epitaxial layer.

[0016] As a preferred technical solution, the light-emitting unit includes a first type cladding layer, a first waveguide layer, an active layer, a second waveguide layer, and a second type cladding layer stacked sequentially from bottom to top.

[0017] As a preferred technical solution, the cross-sectional shape of the isolation groove is an inverted trapezoid.

[0018] A second aspect of the present invention provides a high-power semiconductor laser single tube, which is obtained by bar cleavage of the high-power semiconductor laser described in the above-described technical solution.

[0019] The beneficial effects of this invention are as follows: This invention utilizes two symmetrically arranged front narrowing slots and / or two rear narrowing slots on both sides of the epitaxial layer. The two front narrowing slots are respectively connected to two isolation slots. The two front narrowing slots are located between the front emitting surface of the laser unit and the current injection region, and the minimum spacing between the two front narrowing slots is less than the width of the current injection region. Similarly, the two rear narrowing slots are respectively connected to two isolation slots. The two rear narrowing slots are located between the rear emitting surface of the laser unit and the current injection region, and the minimum spacing between the two rear narrowing slots is less than the width of the current injection region. This structure allows the epitaxial layer to achieve… The width is narrowed near the front and / or rear emitting surfaces of the laser unit, thereby achieving separation and limitation of the near-field spot width and the width of the current injection region T. On the one hand, this reduces the near-field spot width of the bar; on the other hand, since the width of other parts of the epitaxial layer is not reduced, the width of the current injection region is not reduced, and thus the area of ​​the current injection region is not reduced. When injecting a larger pulse current into the current injection region, the injected current density is not increased, thereby improving the reliability of the bar. At the same time, it is easier to fabricate wires in the current injection region, reducing the production cost of the bar. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a schematic diagram of a planar structure of a high-power semiconductor laser bar provided in the first embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the planar structure of the bar section of a high-power semiconductor laser;

[0023] Figure 3 yes Figure 2 A schematic diagram of the cross-sectional structure at point AA shown.

[0024] Figure 4 yes Figure 2 A schematic diagram of the cross-sectional structure at point BB;

[0025] Figure 5 yes Figure 2 A schematic diagram of the cross-sectional structure at point CC is shown.

[0026] Figure 6 yes Figure 2 A schematic cross-sectional view of the epitaxial layer and the first-type substrate of the laser unit of the high-power semiconductor laser bar shown.

[0027] Figure 7 yes Figure 1 The diagram shows a step-by-step flowchart of the fabrication method for a high-power semiconductor laser bar.

[0028] Figures 8 to 14 yes Figure 7 The diagram shows a step-by-step structural diagram of a method for fabricating a high-power semiconductor laser bar.

[0029] Figure 15 This is a schematic diagram of a planar structure of a high-power semiconductor laser bar according to the second embodiment of the present invention;

[0030] Figure 16 This is a schematic diagram of a planar structure of a high-power semiconductor laser bar according to the third embodiment of the present invention;

[0031] Figure 17 This is a schematic diagram of a planar structure of a high-power semiconductor laser bar provided in the fourth embodiment of the present invention.

[0032] Figure label:

[0033] 10. Type I ohmic contact electrode; 20. Type I substrate;

[0034] 30. Laser unit; 31. Epitaxial layer; 311. Light-emitting unit; 3111. Type I cladding; 3112. Type I waveguide layer; 3113. Active layer; 3114. Type II waveguide layer; 3115. Type II cladding; 312. Tunnel junction; 313. Type II ohmic contact layer; 32. Insulating layer; 33. Type II ohmic contact electrode;

[0035] 40. Isolation trench; 41. Side end area; 42. Middle area;

[0036] 50. Front narrowing zone;

[0037] 60. Rear narrowing zone. Detailed Implementation

[0038] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.

[0039] First Embodiment

[0040] Please refer to Figure 1The first embodiment of the present invention provides a high-power semiconductor laser bar, including a first-type ohmic contact electrode 10, a first-type substrate 20, and a plurality of laser units 30. The first-type substrate 20 is an N-type substrate or a P-type substrate, and the first-type ohmic contact electrode 10 is an N-type ohmic contact electrode.

[0041] Combination Figures 2 to 5 As shown, multiple laser units 30 are arranged along a first direction and periodically spaced on one side of a first-type substrate 20. The first-type substrate 20 provides support for the multiple laser units 30, and the number of laser units 30 can be set according to actual conditions. The first direction is, for example, the length direction of the first-type substrate 20, etc., but it is understood that the first direction can also be other. A first-type ohmic contact electrode 10 is disposed on the other side of the first-type substrate 20.

[0042] The laser unit 30 includes an epitaxial layer 31 disposed on one side of the first type substrate 20. The epitaxial layer 31 is located between two isolation trenches 40, and a current injection region T is provided on the mesa of the epitaxial layer 31. The isolation trenches 40 can effectively reduce the lateral diffusion of current. The cross-sectional shape of the isolation trenches 40 is an inverted trapezoid. Understandably, the cross-sectional shape of the isolation trenches 40 can also be other, and can be set according to the actual situation.

[0043] Two forward narrowing slots are symmetrically arranged on both sides of the epitaxial layer 31. These two slots are connected to two isolation slots 40, respectively. The two forward narrowing slots are located between the front emitting surface of the laser unit 30 and the current injection region T. The minimum spacing between the two forward narrowing slots is less than the width of the current injection region T. This structure allows the width of the epitaxial layer 31 to be narrowed near the front emitting surface of the laser unit 30, thereby achieving separation and limitation of the near-field spot width from the width of the current injection region T. On the one hand, this reduces the near-field spot width of the sensor; on the other hand, since the width of other parts of the epitaxial layer 31 is not reduced, the width of the current injection region T is not reduced, thus maintaining the area of ​​the current injection region T. This prevents an increase in the injected current density when injecting a larger pulse current into the current injection region T, thereby improving the reliability of the sensor. Simultaneously, it facilitates wire bonding in the current injection region T, reducing the production cost of the sensor.

[0044] In this embodiment, the front narrowing slot includes a front narrowing region 50, the cross-sectional shape of which is trapezoidal. Understandably, the cross-sectional shape of the front narrowing region 50 can also be other shapes, such as triangles or rectangles, and can be set according to actual conditions. The front narrowing regions 50 of the two front narrowing slots are respectively connected to the two isolation slots 40. The front narrowing regions 50 are located between the front emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the front narrowing regions 50 of the two front narrowing slots is less than the width of the current injection region T.

[0045] In this embodiment, the isolation groove 40 includes a middle region 42 and two side end regions 41. The two side end regions 41 are respectively disposed at both ends of the middle region 42. One side end region 41 is close to the front light-emitting surface of the laser unit 30, and the other side end region 41 is close to the rear light-emitting surface of the laser unit 30. The front narrowing regions 50 of the two front narrowing grooves are respectively connected to the middle region 42 of the two isolation grooves 40.

[0046] The laser unit 30 also includes an insulating layer 32 and a second-type ohmic contact electrode 33. The insulating layer 32 covers the area of ​​the epitaxial layer 31 mesa excluding the current injection region T, the front narrowing regions 50 of the two front narrowing slots, the middle region 42 of the two isolation slots 40, and the side end regions 41 of the two isolation slots 40. The second-type ohmic contact electrode 33 covers the current injection region T, the front narrowing regions 50 of the two front narrowing slots, and the middle region 42 of the two isolation slots 40, and is connected to the insulating layer 32. The second-type ohmic contact electrodes 33 of adjacent laser units 30 are not connected. The second-type ohmic contact electrode 33 is a P-type ohmic contact electrode.

[0047] In this embodiment, the insulating layer 32 is a single-layer passivated insulating film. It can be understood that in other embodiments, the insulating layer 32 may also be a multilayer insulating film composed of a passivated insulating film and a dielectric insulating film. Both the passivated insulating film and the dielectric insulating film are existing and will not be described in detail here.

[0048] The insulating layer 32 protects the bar during output operation, improves its breakdown voltage withstand capability, and enhances its reliability. It also isolates the semiconductor material between the second-type ohmic contact electrode 33 and the isolation groove 40, preventing the bottom / sidewalls of the middle region 42 and the side end region 41 of the isolation groove 40 from failing due to high voltage breakdown, thus reducing the risk of bar damage. The thickness of the insulating layer 32 can be adjusted according to actual conditions. By adjusting the thickness and stress of the insulating layer 32, the risk of side peaks appearing in the slow axis divergence angle of the bar can be reduced, improving the quality of the laser beam. The second-type ohmic contact electrode 33 does not cover the side end regions 41 of the two isolation grooves 40, preventing the bottom / sidewalls of the side end regions 41 from failing due to breakdown, effectively reducing the risk of bar damage.

[0049] Combination Figure 6As shown, the epitaxial layer 31 includes multiple light-emitting units 311, which are arranged sequentially from bottom to top at intervals. Adjacent light-emitting units 311 are connected in series via a tunnel junction 312. Among the multiple light-emitting units 311, the lowest-level light-emitting unit 311 is disposed on one side of the first-type substrate 20, and the surface of the highest-level light-emitting unit 311 is provided with a second-type ohmic contact layer 313. The surface of the second-type ohmic contact layer 313 forms the mesa of the epitaxial layer 31. In this embodiment, there are three light-emitting units 311. It is understood that the number of light-emitting units 311 can be other, such as one, two, four, five, etc., and can be set according to actual conditions. When there is only one light-emitting unit 311, the light-emitting unit 311 is disposed on one side of the first-type substrate 20, and the surface of the light-emitting unit 311 is provided with the second-type ohmic contact layer 313.

[0050] The light-emitting unit 311 includes a first-type cladding layer 3111, a first waveguide layer 3112, an active layer 3113, a second waveguide layer 3114, and a second-type cladding layer 3115, stacked sequentially from bottom to top. The first-type cladding layer 3111 of the bottommost light-emitting unit 311 is disposed on one side of the first-type substrate 20. In two adjacent light-emitting units 311, the second-type cladding layer 3115 of the lower light-emitting unit 311 and the first-type cladding layer 3111 of the uppermost light-emitting unit 311 are connected in series through a tunnel junction 312. The surface of the second-type cladding layer 3115 of the topmost light-emitting unit 311 is provided with a second-type ohmic contact layer 313. The first-type cladding layer 3111 is an N-type cladding layer, and the second-type cladding layer 3115 is a P-type cladding layer.

[0051] Combination Figure 7 As shown, the method for fabricating a high-power semiconductor laser bar according to the present invention includes the following steps:

[0052] Step S10: Provide a first type substrate 20.

[0053] The first type of substrate 20 can be an N-type substrate, such as... Figure 8 As shown, it is made of semiconductor materials.

[0054] Step S20: An epitaxial layer 31 is formed on one side of the first type substrate 20.

[0055] like Figure 9 As shown, the epitaxial layer 31 includes a plurality of light-emitting units 311, which are arranged sequentially from bottom to top at intervals. Adjacent light-emitting units 311 are connected by a tunnel junction 312. The bottommost light-emitting unit 311 is disposed on one side of the first type substrate 20, and the surface of the topmost light-emitting unit 311 is provided with a second type ohmic contact layer 313. The surface of the second type ohmic contact layer 313 forms the mesa of the epitaxial layer 31.

[0056] like Figure 10 As shown, the light-emitting unit 311 includes a first-type cladding layer 3111, a first waveguide layer 3112, an active layer 3113, a second waveguide layer 3114, and a second-type cladding layer 3115, stacked sequentially from bottom to top. The first-type cladding layer 3111 of the bottommost light-emitting unit 311 is disposed on one side of the first-type substrate 20. In two adjacent light-emitting units 311, the second-type cladding layer 3115 of the lower light-emitting unit 311 and the first-type cladding layer 3111 of the upper light-emitting unit 311 are connected in series through a tunnel junction 312. The surface of the second-type cladding layer 3115 of the topmost light-emitting unit 311 is provided with a second-type ohmic contact layer 313.

[0057] Step S30: Etch the epitaxial layer 31 to form two isolation trenches 40 and two front narrowing trenches. For example... Figure 11 and Figure 12 As shown, the front narrowing slot includes a front narrowing region 50, and the isolation slot 40 includes a middle region 42 and two side end regions 41 disposed at both ends of the middle region 42. One side end region 41 is close to the front light-emitting surface of the laser unit 30, and the other side end region 41 is close to the rear light-emitting surface of the laser unit 30. The front narrowing regions 50 of the two front narrowing slots are respectively connected to the middle regions 42 of the two isolation slots.

[0058] Etching can be performed using methods including, but not limited to, wet chemical etching or dry etching.

[0059] Step S40: An insulating layer 32 is formed on the epitaxial layer 31, the two front narrowing grooves, and the two isolation grooves 40. Specifically, as shown in... Figure 13 As shown, an insulating layer 32 is formed on the mesa of the epitaxial layer 31, the front narrowing region 50 of the two front narrowing grooves, the middle region 42 of the two isolation grooves 40, and the side end region 41 of the two isolation grooves 40 by physical methods such as evaporation coating and sputtering coating or by chemical vapor deposition.

[0060] Step S50: A current injection region T is formed on the mesa of the epitaxial layer 31.

[0061] like Figure 14 As shown, the insulating layer 32 and the second-type ohmic contact layer 313 can be etched using chemical etching or dry etching methods to form the current injection region T. The front narrowing region 50 is located between the front emitting surface of the laser unit 30 and the current injection region T, and the minimum spacing between the front narrowing regions 50 of the two front narrowing grooves is less than the width of the current injection region T.

[0062] Step S60: Form a second type of ohmic contact electrode 33 in the current injection region T, the two front narrowing grooves and the two isolation grooves 40. Specifically, form the second type of ohmic contact electrode 33 in the current injection region T, the front narrowing region 50 of the two front narrowing grooves and the middle region 42 of the two isolation grooves by electroplating, evaporation or sputtering, and connect the second type of ohmic contact electrode 33 to the insulating layer 32.

[0063] Step S70: Thin the first type substrate 20 and form a first type ohmic contact electrode 10 on the other side of the first type substrate 20. Thinning can be performed by methods including but not limited to grinding, polishing and etching, and the first type ohmic contact electrode 10 can be fabricated by methods including but not limited to evaporation deposition or sputtering deposition.

[0064] Second Embodiment

[0065] Please refer to Figure 15 The parts identical to those in the first embodiment will not be repeated here. The difference between this embodiment and the first embodiment is that two symmetrically arranged back narrowing slots are provided on both sides of the epitaxial layer 31. These two back narrowing slots are connected to two isolation slots 40, respectively. The two back narrowing slots are located between the rear emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the two back narrowing slots is less than the width of the current injection region T. This structure allows the width of the epitaxial layer 31 to be narrowed near the rear emitting surface of the laser unit 30, thereby achieving separation and limitation of the near-field beam width and the width of the current injection region T. On the one hand, it reduces the near-field beam width of the sensor; on the other hand, since the width of other parts of the epitaxial layer 31 is not reduced, the width of the current injection region T is not reduced, thus maintaining the area of ​​the current injection region T. This prevents an increase in the injected current density when injecting a larger pulse current into the current injection region T, thereby improving the reliability of the sensor. It also facilitates wire bonding in the current injection region T, reducing the production cost of the sensor.

[0066] The rear narrowing slot includes two rear narrowing regions 60, which are designated as a first rear narrowing region and a second rear narrowing region, respectively. The first and second rear narrowing regions of the two slots are connected to two isolation slots 40. The first and second rear narrowing regions are located between the rear emitting surface of the laser unit 30 and the current injection region T, and are sequentially spaced along a direction close to the rear emitting surface of the laser unit 30. The minimum distance between the first rear narrowing regions of the two slots is equal to the width of the current injection region T, and the minimum distance between the second rear narrowing regions of the two slots is less than the width of the current injection region T. The cross-sectional shape of both the first and second rear narrowing regions is triangular; however, it can also be trapezoidal, rectangular, etc., depending on the actual situation. The rear narrowing slot, including two rear narrowing regions 60, is more conducive to the dissipation of higher-order modes, thus suppressing the appearance of side peaks in the divergence angle along the slow axis of the bar.

[0067] The isolation groove 40 includes a central region 42 and two side end regions 41. The two side end regions 41 are respectively located at both ends of the central region 42. One side end region 41 is close to the front light-emitting surface of the laser unit 30, and the other side end region 41 is close to the rear light-emitting surface of the laser unit 30. The first and second rear narrowing regions of the two rear narrowing grooves are respectively connected to the central region 42 of the two isolation grooves 40.

[0068] The insulating layer 32 covers the area of ​​the epitaxial layer 31 mesa except for the current injection region T, the first and second rear narrowing regions of the two rear narrowing grooves, the intermediate region 42 of the two isolation grooves 40, and the side end regions 41 of the two isolation grooves 40. The second-type ohmic contact electrode 33 covers the current injection region T, the first and second rear narrowing regions of the two rear narrowing grooves, and the intermediate region 42 of the two isolation grooves 40. This structure achieves the same technical effect as the first embodiment.

[0069] The method for fabricating the high-power semiconductor laser bar in this embodiment is basically the same as that in the first embodiment, and also includes steps S10-S70:

[0070] Steps S10 and S20 in this embodiment are the same as those in the first embodiment, and will not be repeated here.

[0071] Step S30: Etch the epitaxial layer 31 to form two isolation trenches 40 and two back narrowing trenches. Each back narrowing trench includes two back narrowing regions 60, which are designated as a first back narrowing region and a second back narrowing region, respectively. Each isolation trench 40 includes a central region 42 and two side regions 41 disposed at both ends of the central region 42. One side region 41 is close to the front emitting surface of the laser unit 30, and the other side region 41 is close to the rear emitting surface of the laser unit 30. The first and second back narrowing regions of the two back narrowing trenches are connected to the central region 42 of the two isolation trenches 40.

[0072] Etching can be performed using methods including, but not limited to, wet chemical etching or dry etching.

[0073] Step S40: An insulating layer 32 is formed on the epitaxial layer 31, the two back narrowing grooves and the two isolation grooves 40.

[0074] Specifically, an insulating layer 32 is formed on the mesa of the epitaxial layer 31, the first post-narrowing region of the two post-narrowing grooves, the second post-narrowing region of the two post-narrowing grooves, the middle region 42 of the two isolation grooves 40, and the side end region 41 of the two isolation grooves 40 by physical methods such as evaporation coating and sputtering coating or by chemical vapor deposition.

[0075] Step S50: A current injection region T is formed on the mesa of the epitaxial layer 31.

[0076] The insulating layer 32 and the second type ohmic contact layer 313 can be etched using chemical etching or dry etching methods to form the current injection region T. The first and second back narrowing regions are located between the rear emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the first back narrowing regions of the two back narrowing grooves is equal to the width of the current injection region T, and the minimum distance between the second back narrowing regions of the two back narrowing grooves is less than the width of the current injection region T.

[0077] Step S60: Form a second type of ohmic contact electrode 33 in the current injection region T, the two back narrowing grooves and the two isolation grooves 40. Specifically, the second type of ohmic contact electrode 33 is formed on the current injection region T, the first back narrowing region of the two back narrowing grooves, the second back narrowing region of the two back narrowing grooves and the middle region 42 of the two isolation grooves 40 by electroplating, evaporation or sputtering, and the second type of ohmic contact electrode 33 is connected to the insulating layer 32.

[0078] Step S70 in this embodiment is the same as step 70 in the first embodiment, and will not be described again here.

[0079] Third Embodiment

[0080] Please refer to Figure 16The parts that are the same as in the first embodiment will not be described again. The difference between this embodiment and the first embodiment is that two front narrowing slots and two rear narrowing slots are symmetrically arranged on both sides of the epitaxial layer 31. The two front narrowing slots are respectively connected to two isolation slots 40. The two front narrowing slots are located between the front emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the two front narrowing slots is less than the width of the current injection region T. The two rear narrowing slots are respectively connected to two isolation slots 40. The two rear narrowing slots are located between the rear emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the two rear narrowing slots is less than the width of the current injection region T. This structure allows the width of the epitaxial layer 31 to be narrowed near the front and rear light-emitting surfaces of the laser unit 30, thereby achieving separation and limitation of the near-field spot width and the width of the current injection region T. On the one hand, it can reduce the near-field spot width of the bar; on the other hand, since the width of other parts of the epitaxial layer 31 is not reduced, the width of the current injection region T will not be reduced, and thus the area of ​​the current injection region T will not be reduced. When injecting a larger pulse current into the current injection region T, the injected current density will not increase, thereby improving the reliability of the bar. At the same time, it is easier to fabricate wires in the current injection region T, reducing the production cost of the bar.

[0081] The front narrowing slot includes two front narrowing regions 50, namely a first front narrowing region and a second front narrowing region. The first and second front narrowing regions of the two front narrowing slots are respectively connected to two isolation slots 40. The first and second front narrowing regions are located between the front emitting surface of the laser unit 30 and the current injection region T, and are arranged alternately along the direction close to the front emitting surface of the laser unit 30. The minimum distance between the first front narrowing regions of the two front narrowing slots is equal to the width of the current injection region T, and the minimum distance between the second front narrowing regions of the two front narrowing slots is less than the width of the current injection region T. The cross-sectional shape of the first and second front narrowing regions is triangular. Understandably, it can also be, for example, trapezoidal, rectangular, etc., which can be set according to the actual situation. The rear narrowing slot includes a rear narrowing region 60. The rear narrowing regions 60 of the two rear narrowing slots are respectively connected to two isolation slots 40. The rear narrowing regions 60 are located between the rear emitting surface of the laser unit 30 and the current injection region T. The minimum spacing between the rear narrowing regions 60 of the two rear narrowing slots is less than the width of the current injection region T. The cross-sectional shape of the rear narrowing region 60 is trapezoidal, but it can also be, for example, triangular or rectangular, depending on the actual situation. The front narrowing slot includes two front narrowing regions 50, which is more conducive to the dissipation of higher-order modes and to suppress the appearance of side peaks in the divergence angle of the slow axis of the bar.

[0082] The isolation groove 40 includes a middle region 42 and two side end regions 41. The two side end regions 41 are respectively located at both ends of the middle region 42. One side end region 41 is close to the front light-emitting surface of the laser unit 30, and the other side end region 41 is close to the rear light-emitting surface of the laser unit 30. The first front narrowing region and the second front narrowing region of the two front narrowing grooves are respectively connected to the middle region 42 of the two isolation grooves 40, and the rear narrowing region 60 of the two rear narrowing grooves are respectively connected to the middle region 42 of the two isolation grooves 40.

[0083] The insulating layer 32 covers the area of ​​the epitaxial layer 31 mesa except for the current injection region T, the first front narrowing region of the two front narrowing grooves, the second front narrowing region of the two front narrowing grooves, the rear narrowing region 60 of the two rear narrowing grooves, the middle region 42 of the two isolation grooves 40, and the side end regions 41 of the two isolation grooves 40. The second type ohmic contact electrode 33 covers the current injection region T, the first front narrowing region of the two front narrowing grooves, the second front narrowing region of the two front narrowing grooves, the rear narrowing region 60 of the two rear narrowing grooves, and the middle region 42 of the two isolation grooves 40. This structure can achieve the same technical effect as the first embodiment.

[0084] The method for fabricating the high-power semiconductor laser bar in this embodiment is basically the same as that in the first embodiment, and also includes steps S10-S70:

[0085] Steps S10 and S20 in this embodiment are the same as those in the first embodiment, and will not be repeated here.

[0086] Step S30: Etch the epitaxial layer 31 to form two isolation trenches 40, two front narrowing trenches, and two rear narrowing trenches. Each front narrowing trench includes two front narrowing regions 50, which are respectively a first front narrowing region and a second front narrowing region. Each rear narrowing trench includes a rear narrowing region 60. Each isolation trench 40 includes a central region 42 and two side regions 41 disposed at both ends of the central region 42. One side region 41 is close to the front emitting surface of the laser unit 30, and the other side region 41 is close to the rear emitting surface of the laser unit 30. The first and second front narrowing regions of the two front narrowing trenches are connected to the central region 42 of the two isolation trenches, respectively. The rear narrowing regions 60 of the two rear narrowing trenches are also connected to the central region 42 of the two isolation trenches, respectively.

[0087] Etching can be performed using methods including, but not limited to, wet chemical etching or dry etching.

[0088] Step S40: An insulating layer 32 is formed on the epitaxial layer 31, the two front narrowing grooves, the two rear narrowing grooves and the two isolation grooves 40.

[0089] Specifically, an insulating layer 32 is formed on the mesa of the epitaxial layer 31, the first front narrowing region of the two front narrowing grooves, the second front narrowing region of the two front narrowing grooves, the rear narrowing region 60 of the two rear narrowing grooves, the middle region 42 of the two isolation grooves 40, and the side end region 41 of the two isolation grooves 40 by physical methods such as evaporation coating and sputtering coating or by chemical vapor deposition.

[0090] Step S50: A current injection region T is formed on the mesa of the epitaxial layer 31.

[0091] The insulating layer 32 and the second-type ohmic contact layer 313 can be etched using chemical etching or dry etching methods to form the current injection region T. The first and second front narrowing regions are located between the front emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the first front narrowing regions of the two front narrowing slots is equal to the width of the current injection region T, and the minimum distance between the second front narrowing regions of the two front narrowing slots is less than the width of the current injection region T. The rear narrowing region 60 is located between the rear emitting surface of the laser unit 30 and the current injection region T. The minimum distance between the rear narrowing regions 60 of the two rear narrowing slots is less than the width of the current injection region T.

[0092] Step S60: A second type of ohmic contact electrode 33 is formed in the current injection region T, the two front narrowing grooves, the two rear narrowing grooves, and the two isolation grooves 40. Specifically, the second type of ohmic contact electrode 33 is formed in the current injection region T, the first front narrowing region of the two front narrowing grooves, the second front narrowing region of the two front narrowing grooves, the rear narrowing region 60 of the two rear narrowing grooves, and the middle region 42 of the two isolation grooves using electroplating, evaporation, or sputtering methods, and the second type of ohmic contact electrode 33 is connected to the insulating layer 32.

[0093] Step S70 in this embodiment is the same as step 70 in the first embodiment, and will not be described again here.

[0094] Fourth embodiment

[0095] Please refer to Figure 17 The parts that are the same as those in the first embodiment will not be described again. The difference between this embodiment and the first embodiment is that the second type ohmic contact electrode 33 covers the current injection region T. This embodiment can achieve the same technical effect as the first embodiment.

[0096] The method for fabricating the high-power semiconductor laser bar in this embodiment is basically the same as that in the first embodiment, and also includes steps S10-S70:

[0097] Steps S10, S20, S30, S40, and S50 in this embodiment are the same as steps S10, S20, S30, S40, and S50 in the first embodiment, and will not be repeated here.

[0098] Step S60: Form a second type ohmic contact electrode 33 in the current injection region T. Specifically, the second type ohmic contact electrode 33 is formed on the current injection region T by electroplating, evaporation or sputtering.

[0099] Step S70 in this embodiment is the same as step 70 in the first embodiment, and will not be described again here.

[0100] The present invention also provides a high-power semiconductor laser single tube, which is obtained by the above-mentioned high-power semiconductor laser bar stripe cleavage.

[0101] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A high-power semiconductor laser bar, comprising a first-type ohmic contact electrode, a first-type substrate, and a plurality of laser units, wherein the plurality of laser units are arranged along a first direction and disposed on one side of the first-type substrate, the first-type ohmic contact electrode is disposed on the other side of the first-type substrate, each laser unit includes an epitaxial layer, the epitaxial layer is disposed on one side of the first-type substrate and located between two isolation trenches, and a current injection region is provided on the mesa of the epitaxial layer, characterized in that, The epitaxial layer is symmetrically provided with two front narrowing slots and / or two rear narrowing slots on both sides. The two front narrowing slots are respectively connected to two isolation slots. The two front narrowing slots are located between the front emitting surface of the laser unit and the current injection region. The minimum distance between the two front narrowing slots is less than the width of the current injection region. The two rear narrowing slots are respectively connected to two isolation slots. The two rear narrowing slots are located between the rear emitting surface of the laser unit and the current injection region. The minimum distance between the two rear narrowing slots is less than the width of the current injection region.

2. The high-power semiconductor laser bar according to claim 1, characterized in that, Two front narrowing slots are symmetrically arranged on both sides of the epitaxial layer; each front narrowing slot includes a front narrowing region, and the front narrowing regions of the two front narrowing slots are respectively connected to two isolation slots. The front narrowing region is located between the front light-emitting surface of the laser unit and the current injection region. The minimum distance between the front narrowing regions of the two front narrowing slots is less than the width of the current injection region. The cross-sectional shape of the front narrowing region is trapezoidal, triangular or rectangular.

3. The high-power semiconductor laser bar according to claim 1, characterized in that, The epitaxial layer is symmetrically provided with two front narrowing slots and two rear narrowing slots on both sides; the front narrowing slot includes two front narrowing regions, namely a first front narrowing region and a second front narrowing region. The first front narrowing region and the second front narrowing region of the two front narrowing slots are respectively connected to two isolation slots. The first front narrowing region and the second front narrowing region are located between the front light-emitting surface of the laser unit and the current injection region, and the two are arranged alternately along the direction close to the front light-emitting surface of the laser unit. The minimum distance between the first front narrowing regions of the two front narrowing slots is equal to the width of the current injection region, and the minimum distance between the second front narrowing regions of the two front narrowing slots is less than the width of the current injection region. The rear narrowing slot includes a rear narrowing region. The rear narrowing regions of the two rear narrowing slots are respectively connected to two isolation slots. The rear narrowing region is located between the rear light-emitting surface of the laser unit and the current injection region. The minimum distance between the rear narrowing regions of the two rear narrowing slots is less than the width of the current injection region. The cross-sectional shape of the first and second front narrowing regions is trapezoidal, triangular, or rectangular, and the cross-sectional shape of the rear narrowing region is trapezoidal, triangular, or rectangular.

4. The high-power semiconductor laser bar according to claim 1, characterized in that, Two back narrowing grooves are symmetrically arranged on both sides of the epitaxial layer; each back narrowing groove includes two back narrowing regions, namely a first back narrowing region and a second back narrowing region. The first and second back narrowing regions of the two back narrowing grooves are respectively connected to two isolation grooves. The first and second back narrowing regions are located between the rear emitting surface of the laser unit and the current injection region, and are arranged alternately along the direction close to the rear emitting surface of the laser unit. The minimum distance between the first back narrowing regions of the two back narrowing grooves is equal to the width of the current injection region, and the minimum distance between the second back narrowing regions of the two back narrowing grooves is less than the width of the current injection region. The cross-sectional shape of the first and second back narrowing regions is trapezoidal, triangular, or rectangular.

5. The high-power semiconductor laser bar according to claim 1, characterized in that, The isolation groove includes a middle area and two side end areas. The two side end areas are respectively located at both ends of the middle area. One side end area is close to the front light-emitting surface of the laser unit, and the other side end area is close to the rear light-emitting surface of the laser unit.

6. The high-power semiconductor laser bar according to claim 5, characterized in that, The epitaxial layer has two symmetrically arranged front narrowing grooves on both sides, and the two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode. The insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two front narrowing grooves, the middle area of ​​the two isolation grooves, and the side end areas of the two isolation grooves. The second type ohmic contact electrode covers the current injection area, the two front narrowing grooves, and the middle area of ​​the two isolation grooves.

7. The high-power semiconductor laser bar according to claim 5, characterized in that, The epitaxial layer has two symmetrically arranged front narrowing grooves on both sides, and the two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode. The insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two front narrowing grooves, the middle area of ​​the two isolation grooves, and the side end areas of the two isolation grooves. The second type ohmic contact electrode covers the current injection area.

8. The high-power semiconductor laser bar according to claim 5, characterized in that, The epitaxial layer has two front narrowing grooves and two rear narrowing grooves symmetrically arranged on both sides. The two front narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves, and the two rear narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves. The laser unit also includes an insulating layer and a second type ohmic contact electrode. The insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two front narrowing grooves, the two rear narrowing grooves, the middle area of ​​the two isolation grooves, and the side end areas of the two isolation grooves. The second type ohmic contact electrode covers the current injection area, the two front narrowing grooves, the two rear narrowing grooves, and the middle area of ​​the two isolation grooves.

9. The high-power semiconductor laser bar according to claim 5, characterized in that, The epitaxial layer has two symmetrically arranged back narrowing grooves on both sides, and the two back narrowing grooves are respectively connected to the middle area of ​​the two isolation grooves; the laser unit also includes an insulating layer and a second type ohmic contact electrode. The insulating layer covers the area of ​​the epitaxial layer mesa other than the current injection area, the two back narrowing grooves, the middle area of ​​the two isolation grooves, and the side end area of ​​the two isolation grooves. The second type ohmic contact electrode covers the current injection area, the two back narrowing grooves, and the middle area of ​​the two isolation grooves.

10. The high-power semiconductor laser bar according to claim 1, characterized in that, The epitaxial layer includes a light-emitting unit disposed on one side of the first-type substrate, and the surface of the light-emitting unit is provided with a second-type ohmic contact layer, or... The epitaxial layer includes multiple light-emitting units, which are arranged sequentially from bottom to top at intervals. Two adjacent light-emitting units are connected in series through a tunnel junction. Among the multiple light-emitting units, the bottommost light-emitting unit is disposed on one side of the first type substrate, and the surface of the topmost light-emitting unit is provided with a second type ohmic contact layer. The surface of the second type of ohmic contact layer forms the mesa of the epitaxial layer.

11. The high-power semiconductor laser bar according to claim 10, characterized in that, The light-emitting unit includes a first type cladding layer, a first waveguide layer, an active layer, a second waveguide layer, and a second type cladding layer stacked sequentially from bottom to top.

12. The high-power semiconductor laser bar according to claim 1, characterized in that, The cross-sectional shape of the isolation groove is an inverted trapezoid.

13. A high-power semiconductor laser single tube, characterized in that, The high-power semiconductor laser single tube is obtained by bar cleavage of the high-power semiconductor laser as described in any one of claims 1-12.

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