A semiconductor laser chip with a convenient cleavage and its manufacturing method

Abstract

The application relates to a semiconductor laser chip with conveniently cleaved and arranged bars and a manufacturing method thereof. The chip comprises an epitaxial wafer, the P face of the epitaxial wafer is provided with bars and pad strips, the bars and the pad strips are alternately arranged at intervals to form cleaving windows between the bars and the pad strips, the bars are provided with die structures, the N face of the epitaxial wafer is provided with bar areas and pad strip areas, and the positions of the bar areas and the pad strip areas correspond to the positions of the P face bars and the P face pad strips. The chip structure with the periodically distributed bars and the pad strips at intervals can sequentially cleave the bars and the pad strips at one time during the cleaving operation. When the bars and the pad strips are arranged manually, the bars and the pad strips can be sequentially arranged on a film-coated clamp at intervals, and the operation is convenient and simple. Compared with the conventional cleaving process of first cleaving the bars, then cleaving the pad strips, and finally taking the bars and the pad strips to arrange the bars, the working time is reduced, and the working efficiency is improved.

Description

Technical Field

[0001] This invention relates to a semiconductor laser chip with easily cleaved pendulum bars and its fabrication method, belonging to the field of semiconductor lasers. Background Technology

[0002] Semiconductor lasers have advantages such as small size, light weight, and low power consumption, and are widely used in laser printing and printing, optical communication, optical measurement, robotics and automatic control, beauty, medical and other fields.

[0003] To improve the output power and reliability of semiconductor lasers, optical films are usually deposited on the laser bar cavity surface. The conventional process is to first cut the laser chip into bars, cut the silicon wafer or gallium arsenide substrate with silicon oxide insulating layer into spacers of the same size as the bars, then manually arrange the bars and spacers in a coating fixture at intervals, and finally place the fixture filled with bars and spacers in a vacuum coating equipment to deposit the optical film.

[0004] In recent years, high-vacuum automated cleaving and arranging equipment has gradually developed, especially in the fabrication of high-power semiconductor lasers. This equipment typically operates within a high-vacuum chamber, automatically cleaving the laser chip into bars according to specific rules and arranging them one by one in a fixture. The cavity surface then undergoes pretreatment with plasma cleaning or passivation. After the pretreated bars are removed from the high-vacuum chamber, they need to be manually removed from the fixture for a secondary arranging process, where the bars and spacers are manually arranged alternately on a coating fixture. Finally, the optical film is deposited. However, in automated cleaving and arranging equipment, the bars are in close contact with the P / N metal electrodes of the epitaxial wafer, which easily leads to intermetallic diffusion and adhesion under high-temperature, high-vacuum conditions, making bar separation difficult. Furthermore, the process of bar separation, spacer cleaving, and secondary arranging before optical film deposition is complex and cumbersome, and easily introduces uncontrollable factors such as contamination and scratches, resulting in low production efficiency and yield. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a semiconductor laser chip with easily cleaved pendulum bars and a method for fabricating the same.

[0006] The technical solution of the present invention is as follows:

[0007] A semiconductor laser chip with easily cleaved bar strips is disclosed. The chip includes an epitaxial wafer. Bar strips and spacer strips are disposed on the P-side of the epitaxial wafer. The bar strips and spacer strips are spaced apart and alternately arranged to form cleaving windows between the bar strips and spacer strips. A die structure is disposed on the bar strip. A bar strip region and a spacer strip region are disposed on the N-side of the epitaxial wafer. The positions of the bar strip region and spacer strip region correspond to the positions of the bar strips and spacer strips on the P-side.

[0008] According to a preferred embodiment of the present invention, the number of bar strips is 10 to 50, and the number of spacer strips is 10 to 52, ensuring that the number of spacer strips is greater than or equal to the number of bar strips. The specific number can be adjusted reasonably according to needs and the size of the epitaxial sheet.

[0009] According to a preferred embodiment of the present invention, both the bar strip and the pad strip are cuboids, and the bar strip and the pad strip have the same dimensions: 10-20 mm in length, 1-6 mm in width, and 100-150 μm in height. The specific dimensions can be set as needed.

[0010] According to a preferred embodiment of the present invention, the width of the bar strip area is the sum of the width of the bar strip and half the width of the cleavage windows on both sides, and the width of the pad strip area is the sum of the width of the pad strip and half the width of the cleavage windows on both sides of the pad strip.

[0011] According to a preferred embodiment of the present invention, the die structure is covered with a P-side electrode and the spacer is covered with an insulating layer; the bar area is covered with an N-side electrode and the spacer area is covered with an insulating layer, and the cleavage window is sequentially covered with an insulating layer and a P-side electrode.

[0012] More preferably, the insulating layer is a silicon oxide or silicon nitride insulating layer with a thickness of 50-200 nm.

[0013] According to a preferred embodiment of the present invention, the number of die structures on the bar is N, the die structures are arranged periodically, and N≥1. The fabrication process of the die structures is existing common knowledge. In actual operation, the die structure on the bar on the P-side of the chip can be a single structure or multiple structures.

[0014] According to a preferred embodiment of the present invention, the width of the cleavage window is 20-100 μm.

[0015] The above-mentioned method for fabricating a semiconductor laser chip with easily cleaved pendulum bars includes the following steps:

[0016] a. Provide an epitaxial wafer;

[0017] b. Prepare bar strips and spacer strips on the P-side of the epitaxial wafer, and then deposit P-side electrodes on the bar strips by vapor deposition;

[0018] c. Deposit an insulating layer on the N-side pad region of the epitaxial wafer;

[0019] d. An N-side electrode is deposited on the N-side bar region of the epitaxial wafer to obtain the chip.

[0020] According to a preferred embodiment of the present invention, the method for fabricating the semiconductor laser chip with easily cleaved pendulum bars specifically includes the following steps:

[0021] (1) Take a substrate and grow a confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a P-confinement layer and a GaAs contact layer on the substrate in sequence to obtain an epitaxial wafer;

[0022] (2) Take the epitaxial wafer prepared in step (1), coat the P-side of the epitaxial wafer with photoresist, bake and cure it; then expose and develop it, and obtain the bar strip and the pad strip through photolithography and etching processes. Continue to etch the die structure on the bar strip through photolithography and etching processes.

[0023] (3) An insulating layer is deposited on the P-surface of the epitaxial wafer, and then the insulating layer on the surface of the bar is removed by photolithography and etching processes, so that the surface of the pad and the cleavage window are covered with an insulating layer, while the surface of the bar is not covered with an insulating layer.

[0024] (4) P electrodes are deposited on the P surface of the epitaxial wafer, and then the P electrode on the surface of the pad is removed by photolithography negative resist stripping process, so that the P electrode is covered on the surface of the pad and the cleavage window, and the P electrode is not covered on the surface of the pad.

[0025] (5) Take the epitaxial wafer after step (4), grind and polish the N-side of the epitaxial wafer, then deposit an insulating layer in the N-side pad area, and evaporate the N-side electrode in the N-side bar area.

[0026] All techniques not described in detail in this invention are conventional techniques already existing in the field.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention relates to a chip structure with periodically distributed bar strips and pad strips. During the cleaving operation, the bar strips and pad strips can be cleaved sequentially in one operation. For manual placement, the bar strips and pad strips are arranged sequentially and alternately on the coating fixture. This operation is convenient and simple, reducing working time and improving efficiency compared to the conventional cleaving process of first cleaving the bar strips, then the pad strips, and finally removing and placing the bar strips and pad strips separately.

[0029] 2. The semiconductor laser chip disclosed in this invention uses bar strips and pad strips spaced apart and has a cleaving window. It is particularly suitable for automatic cleaving and arranging equipment. The bar strips and pad strips can be arranged alternately on the coating fixture in one operation, reducing the processes of strip disassembly and secondary cleaving, avoiding defects such as contamination and scratches that are easily introduced during the process, and effectively improving the pass rate of bar strip cleaving and arranging.

[0030] 3. The present invention deposits an insulating layer on both the P and N sides of the pad strip, so that there is no metal contact between the bar strip and the pad strip. Even in high temperature and high vacuum environments, there will be no metal interdiffusion, which would make it difficult to remove the strip after coating, thus improving production efficiency and output. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the semiconductor laser chip with convenient cleavage bar according to the present invention;

[0032] Figure 2 This is a cross-sectional view of the semiconductor laser chip with facilitated cleavage of the pendulum bars according to the present invention.

[0033] In the figure: 1. Epitaxial wafer, 2. Bar strip, 3. Spacer strip, 4. Cleavage window, 5. Spacer strip P-side insulating layer, 6. Bar strip P-side electrode, 7. Bar strip region, 7-1. Bar strip region N-side electrode, 8. Spacer strip region, 8-1. Spacer strip region N-side insulating layer, 9. Die structure. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] like Figures 1-2 As shown, a semiconductor laser chip with convenient cleavage strips is disclosed. The chip includes an epitaxial wafer 1. Strips 2 and spacers 3 are disposed on the P-side of the epitaxial wafer 1. The strips 2 and spacers 3 are spaced and alternately arranged, forming a cleavage window 4 between the strips 2 and spacers 3. A die structure 9 is disposed on the strips 2. Strip regions 7 and spacers 8 are disposed on the N-side of the epitaxial wafer 1. The positions of strip regions 7 and spacers 8 correspond to the positions of strips 2 and spacers 3 on the P-side. A strip P-side electrode 6 is covered on the die structure 9, and a spacer P-side insulating layer 5 is covered on the spacers 3. A strip N-side electrode 7-1 is covered on the strip region 7, and a spacer N-side insulating layer is covered on the spacer region 8. Strip P-side electrodes 6 and spacer P-side insulating layers 5 are sequentially covered within the cleavage window 4. The insulating layer is a silicon oxide insulating layer with a thickness of 100 nm.

[0037] There are 10 bar strips 2 and 10 spacer strips 3. Both bar strips 2 and spacer strips 3 are cuboids, and the bar strips and spacer strips have the same dimensions: 12 mm long, 4 mm wide, and 120 μm high. The width of the cleavage window 4 is 50 μm. The width of the bar strip region 7 is the sum of the width of bar strip 2 and half the width of the cleavage windows 4 on both sides. The width of the spacer strip region 8 is the sum of the width of spacer strip 3 and half the width of the cleavage windows 4 on both sides of the spacer strip. There are 14 cores 9 arranged periodically.

[0038] Example 2

[0039] A semiconductor laser chip with convenient cleavage bar structure is provided, as described in Example 1, except that the width of the cleavage window 4 is 20 μm.

[0040] Example 3

[0041] A semiconductor laser chip with convenient cleavage bar structure is provided, with the structure described in Example 1, except that the width of the cleavage window 4 is 100 μm.

[0042] Example 4

[0043] The method for fabricating a semiconductor laser chip with easily cleaved pendulum bars as described in Example 1 includes the following steps:

[0044] (1) Take a substrate and grow a confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a P-confinement layer and a GaAs contact layer on the substrate in sequence to obtain an epitaxial wafer;

[0045] (2) Take the epitaxial wafer prepared in step (1), coat the P-side of the epitaxial wafer with photoresist, bake and cure it; then expose and develop it, and obtain the bar strip and the pad strip through photolithography and etching processes. Continue to etch the die structure on the bar strip through photolithography and etching processes.

[0046] (3) An insulating layer is deposited on the P-surface of the epitaxial wafer, and then the insulating layer on the surface of the bar is removed by photolithography and etching processes, so that the surface of the pad and the cleavage window are covered with an insulating layer, while the surface of the bar is not covered with an insulating layer.

[0047] (4) P electrodes are deposited on the P surface of the epitaxial wafer, and then the P electrode on the surface of the pad is removed by photolithography negative resist stripping process, so that the P electrode is covered on the surface of the pad and the cleavage window, and the P electrode is not covered on the surface of the pad.

[0048] (5) Take the epitaxial wafer after step (4), grind and polish the N-side of the epitaxial wafer, then deposit an insulating layer in the N-side pad area, and evaporate the N-side electrode in the N-side bar area.

[0049] Comparative Example 1

[0050] A semiconductor laser chip has a P-surface of an epitaxial wafer entirely composed of periodically arranged bar structures with no padding areas. There are cleavage windows between the bars, with a cleavage window width of 50 μm. The bars are 15 mm long and 4 mm wide.

[0051] Comparative Example 2

[0052] A semiconductor laser chip, with the structure described in Example 1, except that the width of the cleavage window 4 is 10 μm.

[0053] Test case

[0054] The semiconductor laser chips described in Embodiment 1 and Comparative Examples 1 and 2 of this invention were automatically cleaved using a Loomis LSD-100 automated cleaving bar device. The results are shown in Table 1.

[0055] Table 1

[0056]

[0057] As shown in Table 1, the semiconductor laser chip provided in Example 1, with its alternating arrangement of bar strips and spacer strips, facilitates easier bar cleaving and arranging, making it particularly suitable for automated bar cleaving and arranging equipment. In a single operation, the bar strips and spacer strips can be arranged alternately on the coating fixture, reducing processes such as strip removal and secondary arranging. Compared to Comparative Example 1, the cleaving time is reduced by more than 52%, and compared to Comparative Example 2, it is reduced by more than 26%. Furthermore, this invention deposits an insulating layer on both the P / N surfaces of the spacer strip, eliminating metal contact between the bar strip and the spacer strip. Even in high-temperature, high-vacuum environments, metal interdiffusion does not occur, preventing difficulties in strip removal after coating. Therefore, the number of bar strips exhibiting metal interdiffusion, contamination, and scratches is significantly reduced compared to Comparative Examples 1 and 2. Additionally, the cleaving window width of Example 1 is 50 μm, compared to 10 μm in Comparative Example 2, further reducing the number of bar strips with abnormal cleaving windows. Overall, the bar strip pass rate is significantly improved compared to Comparative Examples 1 and 2.

Claims

1. A semiconductor laser chip with easily cleaved pendulum bars, characterized in that, The chip includes an epitaxial wafer. On the P-side of the epitaxial wafer, there are bar strips and pad strips. The bar strips and pad strips are spaced apart and alternately arranged to form a cleaving window between the bar strips and pad strips. A die structure is provided on the bar strip. On the N-side of the epitaxial wafer, there are bar strip area and pad strip area. The positions of the bar strip area and pad strip area correspond to the positions of the bar strips and pad strips on the P-side.

2. The semiconductor laser chip as described in claim 1, characterized in that, The number of bar strips is 10 to 50, and the number of pad strips is 10 to 52, ensuring that the number of pad strips is greater than or equal to the number of bar strips.

3. The semiconductor laser chip as described in claim 1, characterized in that, Both the bar strip and the pad strip are cuboids, and the bar strip and the pad strip have the same dimensions, with a length of 10~20mm, a width of 1~6mm, and a height of 100~150μm.

4. The semiconductor laser chip as described in claim 1, characterized in that, The width of the bar strip area is the sum of the width of the bar strip and half the width of the cleavage windows on both sides, and the width of the pad strip area is the sum of the width of the pad strip and half the width of the cleavage windows on both sides of the pad strip.

5. The semiconductor laser chip as described in claim 1, characterized in that, The die structure is covered with a P-side electrode, and the spacer is covered with an insulating layer; the bar area is covered with an N-side electrode, the spacer area is covered with an insulating layer, and the cleavage window is sequentially covered with an insulating layer and a P-side electrode.

6. The semiconductor laser chip as described in claim 5, characterized in that, The insulating layer is a silicon oxide or silicon nitride insulating layer with a thickness of 50~200nm.

7. The semiconductor laser chip as described in claim 1, characterized in that, The number of core structures on the bar is N, and the core structures are arranged periodically, with N≥1.

8. The semiconductor laser chip as described in claim 1, characterized in that, The width of the cleavage window is 20~100μm.

9. The method for fabricating a semiconductor laser chip with easily cleaved pendulum bars as described in claim 1, characterized in that, Includes the following steps: a. Provide an epitaxial wafer; b. Prepare bar strips and spacer strips on the P-side of the epitaxial wafer, and then deposit P-side electrodes on the bar strips by vapor deposition; c. Deposit an insulating layer on the N-side pad region of the epitaxial wafer; d. An N-side electrode is deposited on the N-side bar region of the epitaxial wafer to obtain the chip.

10. The method for fabricating a semiconductor laser chip with easily cleaved pendulum bars as described in claim 9, characterized in that, Specifically, the following steps are included: (1) Take a substrate and grow a confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a P-confinement layer and a GaAs contact layer on the substrate in sequence to obtain an epitaxial wafer; (2) Take the epitaxial wafer prepared in step (1), coat the P-side of the epitaxial wafer with photoresist, bake and cure it; then expose and develop it, and obtain the bar strip and the pad strip through photolithography and etching process, and continue to etch the die structure on the bar strip through photolithography and etching process. (3) An insulating layer is deposited on the P-surface of the epitaxial wafer, and then the insulating layer on the surface of the bar is removed by photolithography and etching processes, so that the surface of the pad and the cleavage window are covered with an insulating layer, while the surface of the bar is not covered with an insulating layer. (4) P electrodes are deposited on the P surface of the epitaxial wafer, and then the P-side electrodes on the surface of the pad are removed by photolithography negative resist stripping process, so that the P-side electrodes are covered on the surface of the pad and in the cleavage window, and the P-side electrodes are not covered on the surface of the pad. (5) Take the epitaxial wafer after step (4), grind and polish the N-side of the epitaxial wafer, then deposit an insulating layer in the N-side pad area, and evaporate the N-side electrode in the N-side bar area.

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