Optimized spot semiconductor laser and preparation method thereof

Abstract

This invention relates to a semiconductor laser with optimized beam pattern and its fabrication method. A ridge is formed beneath an ohmic contact layer, with shoulder grooves formed on both sides of the ridge. A deep trench reserved buffer zone is formed on one side of the shoulder groove, and a deep trench is formed at the bottom of the deep trench reserved buffer zone. The upper edge of the deep trench and the area at the bottom of the deep trench reserved buffer zone is an oxide reserved region. An oxide reserved layer is formed on the oxide reserved region. Partial areas of the ohmic contact layer, the surface of the shoulder groove, and the surface of the deep trench reserved buffer zone are all covered with an insulating layer; or partial areas of the ohmic contact layer, the surface of the shoulder groove, the surface of the deep trench reserved buffer zone, and the surface of the deep trench are all covered with an insulating layer. A p-plane metal is formed on the upper surface of the insulating layer. The technical solution provided by this invention can optimize the beam pattern, effectively reduce the number of modes generated in the ridge region, and filter the higher-order modes of the generated laser, thereby effectively optimizing the beam pattern.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of spot optimized semiconductor laser and its preparation method, belong to the technical field of semiconductor laser. BACKGROUND

[0002] Semiconductor laser has been developed for decades, and the application field of semiconductor laser is more and more widely, such as illumination, medical cosmetology, communication, industrial laser welding etc..Semiconductor laser has many advantages: small size, light weight, can be injected excitation, wide wavelength range, high coherence, can be mass-produced.But there are also shortcomings in the application process of semiconductor laser, one of which is output light divergence, the end face of output light is emitted in the form of radiation, which is divergent light, and usually needs to be shaped in the process of using.

[0003] Chinese patent document CN209542971U discloses a kind of device for realizing semiconductor laser spot shaping and homogenization, belongs to the field of semiconductor laser packaging, including semiconductor laser, lens pipe cap and spot receiving screen, the pipe cap is packaged in the front end of the light emitting direction of semiconductor laser, the inner hole front portion of the pipe cap is inlaid with convex lens, the main optical axis of the convex lens coincides with the axis of the light emitting direction of semiconductor laser, the spot receiving screen is placed in the front of the light emitting direction of semiconductor laser.But, this patent is realized in the way that the inner hole front portion of pipe cap is inlaid with convex lens in the packaging process of chip. Although with the help of convex lens, the spot can be shaped and homogenized, but the packaging cost is higher, and the quality of chip spot also has certain requirements, and the problem of spot optimization cannot be fundamentally solved.

[0004] Chinese patent document CN105490165A discloses a high-power semiconductor laser with stable beam pattern. From bottom to top, it includes a substrate, a lower cladding layer, an active region, an upper cladding layer, and a contact layer. Ridge structures are formed on the upper cladding layer and the contact layer, with trenches formed on both sides of the ridge structures. The depth of the trenches is less than the total thickness of the upper cladding layer and the contact layer. A dielectric film is coated on the upper surface of the contact layer (excluding the ridges) and the surface of the trenches. A first metal electrode layer is coated on the dielectric film and the ridge structures. A second metal electrode layer is formed on the bottom surface of the substrate. The first metal electrode layer is sintered onto a heat sink with solder, and an air isolation layer is provided between the solder and the bottom of the trenches. In this laser, the upper cladding layer is relatively thick and has a ridge structure. During operation, the lateral heat dissipation path generated by the active region is blocked by the air isolation layer, and the heat is mainly dissipated vertically through the ridge-shaped contact layer. Therefore, the refractive index gradient of the active region in the middle part of the ridge and near the trenches does not continue to increase with increasing heat generation, resulting in a more stable near-field beam pattern. However, in this patent, the semiconductor laser itself already forms a good beam, and the beam is made more stable by suppressing the formation of the thermal lensing effect. However, the first metal layer covers the dielectric film, and during the packaging process, because the solder and the first metal layer have good wettability, the solder can easily fill into the groove, resulting in a low success rate in forming the air isolation group discontinuity.

[0005] If the laser spot can be optimized during the fabrication of laser semiconductor chips, and stray light and higher-order modes can be filtered out, the technical difficulty of spot shaping can be reduced, and the laser stray light can be prevented from burning the fiber end face during fiber coupling. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a semiconductor laser with optimized beam spot, which can effectively reduce the number of modes generated in the ridge region and filter the higher-order modes of the generated laser, thereby effectively optimizing the beam spot.

[0007] In addition, this application also provides a method for fabricating the aforementioned semiconductor laser with optimized light spot.

[0008] The technical solution of this invention is as follows:

[0009] A semiconductor laser with optimized beam pattern includes, from bottom to top, a substrate, an N-confinement layer, an N-waveguide layer, a quantum well active layer, a P-waveguide layer, a P-confinement layer, and an ohmic contact layer.

[0010] A ridge is provided below the ohmic contact layer, and shoulder grooves are formed on both sides of the ridge. A deep groove reserved buffer is provided on one side of the shoulder groove, and the ridge and the deep groove reserved buffer are at a certain angle. The bottom of the shoulder groove is provided on the P-limiting layer, and the depth of the shoulder groove is the same as the depth of the deep groove reserved buffer.

[0011] The bottom of the deep trench reserved buffer zone is provided with a deep trench, and the area at the upper edge of the deep trench and at the bottom of the deep trench reserved buffer zone is the oxide reserved area, and an oxide reserved layer is provided on the oxide reserved area;

[0012] Parts of the ohmic contact layer, the surface of the shoulder groove, and the surface of the deep trench reserved buffer zone are all covered with an insulating layer;

[0013] Or, a portion of the ohmic contact layer, the surface of the shoulder groove, the surface of the reserved buffer zone for the deep trench, and the surface of the deep trench are all covered with an insulating layer;

[0014] The upper surface of the insulating layer is provided with a P-side metal.

[0015] Semiconductor lasers typically produce multi-mode output in the ridge region; the more modes included, the worse the output beam. Adding deep trenches on both sides of the ridge, forming an air isolation layer within the trenches, effectively limits the expansion of the ridge gain region, preventing the generation of more modes. The deep trenches are also fabricated within a reserved buffer zone, which effectively absorbs and blocks excess solder.

[0016] Semiconductor laser users typically use gold-tin encapsulation during operation. Gold-tin solder has extremely poor wettability with non-metallic oxides. The gold-tin solder will preferentially bond with the metal to form a weld. The excess portion can be absorbed and stored in the deep trench buffer zone. The design of the oxide reserve layer further prevents the expansion of the gold-tin solder, providing good conditions for the formation of an air isolation layer in the deep trench.

[0017] In this application, an insulating layer is placed on the surface of the deep trench. The refractive index difference between the insulating layer and the semiconductor material can effectively filter stray light. No insulating layer is placed at the bottom of the deep trench because the refractive index difference between air and the semiconductor material is greater than that between a typical oxide insulating layer and the semiconductor material. This design can effectively filter out already generated higher-order laser modes.

[0018] According to a preferred embodiment of the invention, the bottom of the deep trench passes through the N-waveguide layer and is located within the N-confining layer.

[0019] The trench depth must exceed the active region, with the bottom extending beyond the N-waveguide layer. The trench must cut off the active region to effectively isolate ridge current propagation. Furthermore, because the N-waveguide and P-waveguide layers in a semiconductor laser affect the laser's optical field distribution, the bottom of the trench must also extend beyond the N-waveguide layer to maintain a symmetrical optical field distribution. Based on this, an air isolation layer is formed within the trench, and the semiconductor material exhibits a high refractive index deviation. The presence of the air isolation layer effectively suppresses the number of laser modes generated in the ridge region. For higher-order laser modes, the high refractive index deviation also provides a filtering effect, thus effectively improving the beam quality.

[0020] According to a preferred embodiment of the present invention, the width of the oxide pre-reserved layer is 10-15 μm.

[0021] According to a preferred embodiment of the present invention, the oxide pre-reserved layer and the insulating layer are made of SiO2, Si3N4, or other transparent insulating media.

[0022] According to a preferred embodiment of the present invention, the angle between the ridge and the reserved buffer zone of the deep trench is 0-180°; more preferably, the angle between the ridge and the reserved buffer zone of the deep trench is 45°.

[0023] The deep trench is fabricated within the deep trench buffer zone and oriented in the same direction as the deep trench buffer zone. The angle between the deep trench and the buffer zone is the same as the angle between the ridge and the deep trench. Poor edge morphology of the deep trench can cause laser absorption, which is more pronounced at closer distances, but at greater distances it will affect the improvement of the laser spot morphology. Therefore, a certain angle is chosen between the ridge and the deep trench buffer zone. This can effectively balance the power of the semiconductor laser device and the improvement of the laser spot. A suitable angle can be selected according to the requirements for the laser spot and the requirements for electrical parameters such as power. A 45° angle is preferred to balance these two points.

[0024] According to a preferred embodiment of the invention, the top of the deep groove is parallel to the ridge, or the top of the deep groove is semi-circular.

[0025] The top of the deep groove is closest to the ridge. If a non-0° angle design is used, the distance between the top of the groove and the ridge will vary depending on the shape of the groove. Because the morphology of the ridge edge prepared by different processes will produce certain light absorption, the ideal deep groove edge is a smooth and flat edge. However, this is difficult to achieve in actual preparation. Different shapes can be selected according to the specific implementation of the deep groove edge to balance absorption and laser power.

[0026] According to the present invention, preferably, the distance from the top of the deep groove to the ridge is 0.5-100 μm; preferably, the distance from the top of the deep groove to the ridge is 0.5-2.5 μm.

[0027] The method for fabricating the laser with optimized beam spot described above includes the following steps in sequence:

[0028] (1) An N-confinement layer, an N-waveguide layer, a quantum hydrazine active region, a P-waveguide layer, a P-confinement layer and an ohmic contact layer were sequentially grown on the substrate using the MOCVD method.

[0029] (2) Etching forms shoulder grooves and deep trenches with reserved buffer zones, the depth of which is approximately 0.5-1 μm;

[0030] (3) A deep trench is formed by etching at the bottom of the deep trench reserved buffer zone, and the depth from the bottom of the deep trench to the bottom of the deep trench reserved buffer zone is 0.5-1μm;

[0031] (4) Grow an insulating layer;

[0032] (5) Remove the insulating layer on the ridge by photolithography, etching or stripping to leave a contact area for the next step of P-side ohmic contact;

[0033] (6) Prepare P-side metal by vapor deposition or other methods, and remove the upper edge of the deep trench by peeling or etching to form an oxide pre-reserved layer;

[0034] (7) Depending on the requirements for the quality of the light spot, decide whether to remove the insulating layer on the surface of the deep trench;

[0035] If high spot quality is required, and the proportion of side modes generated by the entire epitaxial wafer is required to be >70%, the insulating layer on the surface of the deep trench can be removed. The disadvantage is that it places higher demands on the packaging process of the laser chip user.

[0036] If the requirements for spot quality are not high, and the requirement for the proportion of side modes generated on the entire epitaxial wafer to be >60%, it is advisable to retain the insulating layer on the surface of the deep trench. Although the proportion of slight side modes generated is slightly lower, the requirements for the packaging process of the laser chip user are lower.

[0037] (8) After substrate thinning, preparation of back metal, alloy treatment, and cleavage, a semiconductor laser chip is finally formed.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. This invention provides a semiconductor laser with optimized beam spot, which can effectively reduce the number of modes generated in the ridge region and filter higher-order modes of the generated laser, thereby effectively optimizing the beam spot. Through optimized design of the deep trench and its reserved area, considering whether the chip is packaged with the P-side down or P-side up, a good refractive index difference and air isolation layer can be formed in the deep trench region. When no insulating layer is provided on the surface of the deep trench, an air refractive index variation layer with a refractive index of 1.0 can be formed in the deep trench region, which can also better filter stray light. When the insulating layer on the surface of the deep trench is silicon oxide, the refractive index is generally around 1.46, which can effectively filter stray light.

[0040] 2. Using the solution provided by this invention, the proportion of chips with slight side molds is increased from the original 14% to more than 75%. Attached Figure Description

[0041] Figure 1 A schematic cross-sectional view of a semiconductor laser provided by the present invention;

[0042] Figure 2 A top view diagram showing the buffer zones reserved for the spine, shoulder groove, and deep groove;

[0043] Figure 3 This is a top view of the chip after the deep trench has been formed.

[0044] Figure 4 A schematic diagram of a cross-section of a semiconductor laser chip structure with an insulating layer.

[0045] Figure 5 A schematic diagram of the cross-section of a semiconductor laser chip after the insulating layer inside the deep trench has been removed.

[0046] Figure 6 Example 4 provides a design scheme for a deep trench and a deep trench reserved area;

[0047] Figure 7 Example 5 provides a design scheme for a deep trench and a deep trench reserved area;

[0048] Figure 8 The improved spot pattern using the technical solution provided in this application;

[0049] Figure 9 The original light spot pattern;

[0050] 1. Substrate, 2. N-confinement layer, 3. N-waveguide layer, 4. Quantum hydrazine active region, 5. P-waveguide layer, 6. P-confinement layer, 7. Ohmic contact layer, 8. Ridge, 9. Shoulder groove, 10. Deep trench reserved buffer zone, 11. Deep trench, 12. Insulating layer, 13. P-plane metal, 14. Oxide reserved layer. Detailed Implementation

[0051] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0052] Example 1

[0053] A semiconductor laser with optimized beam pattern, such as Figure 1 , Figure 2 and Figure 5 As shown, it includes, from bottom to top, a substrate 1, an N-confinement layer 2, an N-waveguide layer 3, a quantum well active layer, a P-waveguide layer 5, a P-confinement layer 6, and an ohmic contact layer 7.

[0054] A ridge 8 is provided below the ohmic contact layer 7, and shoulder grooves 9 are formed on both sides of the ridge 8. A deep groove reserved buffer zone 10 is provided on one side of the shoulder groove 9. The ridge 8 and the deep groove reserved buffer zone 10 are at a certain angle. The bottom of the shoulder groove 9 is provided on the P-limiting layer 6, and the depth of the shoulder groove 9 is the same as the depth of the deep groove reserved buffer zone 10.

[0055] A deep trench 11 is provided at the bottom of the deep trench reserved buffer zone 10. The area at the upper edge of the deep trench 11 and at the bottom of the deep trench reserved buffer zone 10 is the oxide reserved area. An oxide reserved layer 14 is provided on the oxide reserved area.

[0056] A portion of the ohmic contact layer 7, the surface of the shoulder groove 9, and the surface of the deep trench reserved buffer zone 10 are all covered with an insulating layer 12;

[0057] The upper surface of the insulating layer 12 is provided with a P-side metal 13.

[0058] Semiconductor lasers typically produce multi-mode output in the ridge region; the more modes included, the worse the output beam. Adding deep trenches 11 on both sides of the ridge, with an air isolation layer formed within each trench 11, effectively limits the expansion of the ridge's gain region, preventing the generation of more modes. The deep trenches 11 are fabricated within a deep trench buffer zone 10, which effectively absorbs and blocks excess gold-solder solder.

[0059] Semiconductor laser users typically use gold-tin encapsulation during use. Gold-tin solder has extremely poor wettability with non-metallic oxides. The gold-tin solder will preferentially bond with the metal to form a weld. The excess portion can be absorbed and stored in the deep trench reserved buffer 10. The design of the oxide reserved layer 14 further prevents the expansion of the gold-tin solder, providing good conditions for the formation of an air isolation layer in the deep trench 11.

[0060] No insulating layer 12 is provided at the bottom of the deep trench 11 because the refractive index difference formed by air and semiconductor materials is greater than the refractive index difference formed by general oxide insulating layer 12 and semiconductor materials. This design can effectively filter out the generated high-order laser modes.

[0061] Example 2

[0062] The difference between this and the semiconductor laser with optimized beam size provided in Example 1 is that:

[0063] like Figure 4 As shown, a portion of the ohmic contact layer 7, the surface of the shoulder groove 9, the surface of the deep trench reserved buffer zone 10, and the surface of the deep trench 11 are all covered with an insulating layer 12.

[0064] In this application, an insulating layer 12 is provided on the surface of the deep trench 11. The refractive index difference between the insulating layer 12 and the semiconductor material can effectively filter stray light.

[0065] Example 3

[0066] The difference between this and the semiconductor laser with optimized beam size provided in Example 1 is that:

[0067] The bottom of the deep trench 11 passes through the N waveguide layer 3 and is located in the N confinement layer 2.

[0068] The depth of the deep trench 11 must exceed the active region, with the bottom of the trench 11 extending beyond the N-waveguide layer 3. The deep trench 11 must cut off the active region to effectively isolate the current diffusion in the ridge region. Furthermore, because the N-waveguide layer 3 and P-waveguide layer 5 in the semiconductor laser affect the laser's optical field distribution, the bottom of the deep trench 11 must also extend beyond the N-waveguide layer 3 to maintain a symmetrical optical field distribution. Based on this, an air isolation layer is formed within the deep trench 11, and the semiconductor material creates a high refractive index deviation. The presence of the air isolation layer effectively suppresses the number of laser modes generated in the ridge region. For higher-order laser modes, the high refractive index deviation also provides a filtering effect, thereby effectively improving the beam quality.

[0069] The width of the oxide pre-reserved layer 14 is 10-15 μm.

[0070] The oxide pre-reserved layer 14 and the insulating layer 12 are made of SiO2, Si3N4, or other transparent insulating media.

[0071] The angle between the ridge 8 and the reserved buffer zone 10 of the deep trench is 45°.

[0072] The deep trench 11 is fabricated within the deep trench 11 buffer zone and is oriented in the same direction as the deep trench 11 buffer zone. The included angle of the deep trench reserved buffer zone 10 is the included angle between the ridge 8 and the deep trench 11. Poor edge morphology of the deep trench 11 will cause laser absorption, which is more severe the closer the distance, but will affect the improvement of the spot morphology if the distance is far. Therefore, a certain included angle is selected between the ridge 8 and the deep trench 11 buffer zone. This can effectively balance the power of the semiconductor laser device and the effect of spot improvement. A suitable included angle can be selected according to the requirements of the spot and the requirements of power and other electrical parameters. A 45° included angle is preferred to balance these two points.

[0073] like Figure 3 As shown, the top of the deep groove 11 is parallel to the ridge 8. The top of the deep groove 11 is closest to the ridge 8. If a non-0° included angle design is used, the distance between the top of the groove and the ridge 8 will be different for different shapes. Because the morphology of the edge of the ridge 8 prepared by different processes will produce a certain amount of light absorption, the ideal edge of the deep groove 11 is a smooth and flat edge. However, there are certain difficulties in the actual preparation process. Different shapes can be selected according to the specific realization of the edge of the deep groove 11 to balance absorption and laser power.

[0074] The distance from the top of the deep groove 11 to the ridge 8 is 0.5-100 μm.

[0075] After adopting the solution of the present invention, the chip ratio of the side mold is increased from the original 14% to more than 75%.

[0076] like Figure 9 As shown, before the improvement, over 50% of the light spot edges had side modes, and the higher-order modes of the light spot were still quite prevalent. After adopting the optimization scheme of this invention, the edge side modes were significantly reduced, and the optimized light spot pattern is shown in the figure. Figure 8 As shown.

[0077] Example 4

[0078] The difference between this and the semiconductor laser with optimized beam size provided in Example 3 is that:

[0079] A portion of the ohmic contact layer 7, the surface of the shoulder groove 9, the surface of the deep trench reserved buffer zone 10, and the surface of the deep trench 11 are all covered with an insulating layer 12.

[0080] like Figure 6 As shown, the top of the deep groove 11 is semi-circular.

[0081] The distance from the top of the deep groove 11 to the ridge 8 is 0.5-2.5 μm.

[0082] Example 5

[0083] The difference between this and the semiconductor laser with optimized beam size provided in Example 3 is that:

[0084] like Figure 7 As shown, the angle between the ridge 8 and the deep trench reserved buffer zone 10 is 180°.

[0085] Example 6

[0086] Example 3 provides a method for fabricating a semiconductor laser with optimized beam spot, which includes the following steps in sequence:

[0087] (1) An N-confinement layer 2, an N-waveguide layer 3, a quantum hydrazine active region 4, a P-waveguide layer 5, a P-confinement layer 6 and an ohmic contact layer 7 are sequentially grown on substrate 1 using MOCVD.

[0088] (2) Etching forms a shoulder groove 9 and a deep trench reserved buffer zone 10, the depth of which is approximately 0.5-1 μm;

[0089] (3) A deep trench 11 is formed by etching at the bottom of the deep trench reserved buffer zone 10, and the depth from the bottom of the deep trench 11 to the bottom of the deep trench reserved buffer zone 10 is 0.5-1μm;

[0090] (4) Growth of insulating layer 12;

[0091] (5) Remove the insulating layer 12 on the ridge 8 by photolithography, etching or stripping to leave a contact area for the next step of P-side ohmic contact;

[0092] (6) Prepare P-side metal 13 by vapor deposition or other methods, and remove the upper edge of deep trench 11 by peeling or etching to form oxide pre-reserved layer 14;

[0093] (7) When the proportion of slight side molds generated on the entire epitaxial wafer is required to be >70%, the insulating layer 12 on the surface of the deep trench 11 is removed. The disadvantage is that it requires higher packaging process from the laser chip user.

[0094] (8) After substrate 1 is thinned, back metal is prepared, alloy treatment is performed, and cleavage is performed, a semiconductor laser chip is finally formed.

[0095] Example 7

[0096] Example 4 provides a method for fabricating a semiconductor laser with optimized beam spot, comprising the following steps:

[0097] (1) An N-confinement layer 2, an N-waveguide layer 3, a quantum hydrazine active region 4, a P-waveguide layer 5, a P-confinement layer 6 and an ohmic contact layer 7 are sequentially grown on substrate 1 using MOCVD.

[0098] (2) Etching forms a shoulder groove 9 and a deep trench reserved buffer zone 10, the depth of which is approximately 0.5-1 μm;

[0099] (3) A deep trench 11 is formed by etching at the bottom of the deep trench reserved buffer zone 10, and the depth from the bottom of the deep trench 11 to the bottom of the deep trench reserved buffer zone 10 is 0.5-1μm;

[0100] (4) Growth of insulating layer 12;

[0101] (5) Remove the insulating layer 12 on the ridge 8 by photolithography, etching or stripping to leave a contact area for the next step of P-side ohmic contact;

[0102] (6) Prepare P-side metal 13 by vapor deposition or other methods, and remove the upper edge of deep trench 11 by peeling or etching to form oxide pre-reserved layer 14;

[0103] (7) When the proportion of slight side modes generated on the entire epitaxial wafer is required to be >60%, the insulating layer 12 on the surface of the deep trench 11 is retained. Although the proportion of slight side modes generated is slightly lower, the packaging process requirements for laser chip users are lower.

[0104] (8) After substrate 1 is thinned, back metal is prepared, alloy treatment is performed, and cleavage is performed, a semiconductor laser chip is finally formed.

Claims

1. A semiconductor laser with optimized beam spot, characterized in that, It includes, from bottom to top, a substrate, an N-confinement layer, an N-waveguide layer, a quantum well active layer, a P-waveguide layer, a P-confinement layer, and an ohmic contact layer; A ridge is provided below the ohmic contact layer, and shoulder grooves are formed on both sides of the ridge. A deep groove reserved buffer is provided on one side of the shoulder groove, and the ridge and the deep groove reserved buffer are at a certain angle. The bottom of the shoulder groove is provided on the P-limiting layer, and the depth of the shoulder groove is the same as the depth of the deep groove reserved buffer. The bottom of the deep trench reserved buffer zone is provided with a deep trench, and the area at the upper edge of the deep trench and at the bottom of the deep trench reserved buffer zone is the oxide reserved area, and an oxide reserved layer is provided on the oxide reserved area; Parts of the ohmic contact layer, the surface of the shoulder groove, and the surface of the deep trench reserved buffer zone are all covered with an insulating layer; Or, a portion of the ohmic contact layer, the surface of the shoulder groove, the surface of the reserved buffer zone for the deep trench, and the surface of the deep trench are all covered with an insulating layer; The upper surface of the insulating layer is provided with a P-side metal.

2. The semiconductor laser with optimized beam spot according to claim 1, characterized in that, The bottom of the deep trench passes through the N waveguide layer and is located within the N confinement layer.

3. A semiconductor laser with optimized beam spot according to claim 1, characterized in that, The width of the oxide pre-reserved layer is 10-15 μm.

4. A semiconductor laser with optimized beam spot according to claim 1, characterized in that, The oxide pre-reserved layer and the insulating layer are made of SiO2 and Si3N4.

5. A semiconductor laser with optimized beam spot according to claim 1, characterized in that, The angle between the ridge and the buffer zone reserved in the deep trench is 0-180°.

6. A semiconductor laser with optimized beam spot according to claim 5, characterized in that, The angle between the ridge and the buffer zone reserved in the deep trench is 45°.

7. A semiconductor laser with optimized beam spot according to claim 1, characterized in that, The top of the deep groove is parallel to the ridge, or the top of the deep groove is semi-circular.

8. A semiconductor laser with optimized beam spot according to claim 1, characterized in that, The distance from the top of the deep groove to the ridge is 0.5-100 μm.

9. A semiconductor laser with optimized beam spot according to claim 8, characterized in that, The distance from the top of the deep groove to the ridge is 0.5-2.5 μm.

10. A method for fabricating a semiconductor laser with optimized beam spot according to any one of claims 1-9, characterized in that, The steps are as follows: (1) An N-confinement layer, an N-waveguide layer, a quantum hydrazine active region, a P-waveguide layer, a P-confinement layer and an ohmic contact layer are sequentially grown on a substrate. (2) Etching forms shoulder grooves and deep trenches to reserve buffer zones; (3) Etch to form a deep trench at the bottom of the reserved buffer zone of the deep trench; (4) Grow an insulating layer; (5) Remove the insulation layer on the spine; (6) Prepare P-face metal and remove the upper edge of the deep trench to form an oxide pre-reserved layer; (7) Depending on the requirements for the quality of the light spot, decide whether to remove the insulating layer on the surface of the deep trench; (8) After substrate thinning, preparation of back metal, alloy treatment, and cleavage, a semiconductor laser chip is finally formed.

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