High power edge emitting semiconductor laser chip and method of manufacturing the same

Abstract

The application relates to a high-power edge-emitting semiconductor laser chip preparation method, which comprises the following steps: S1, epitaxial growth of a laser structure; S2, forming a mask on the surface of the epitaxially grown wafer and opening a pattern for etching on the mask, wherein the pattern has etching points; S3, etching in the depth direction of the wafer at the etching points to form a groove; S4, removing the oxidation layer in the groove; S5, growing an etching blocking material on the groove wall of the groove to cover the upper surface of the wafer; and S6, continuously performing subsequent production to obtain a chip. The application also provides a high-power edge-emitting semiconductor laser chip. According to the high-power edge-emitting semiconductor laser chip, after the oxidation layer is removed by in-situ etching, a protective material is pre-grown on the chip cutting end face, the aluminum-containing material of the end face is prevented from being exposed to oxidation, and thus end face damage is avoided; the protective material can be an etching blocking material or be composed of the etching blocking material and a protective crystal material.

Description

Technical Field

[0001] This invention relates to the field of laser chip technology, specifically to a high-power side-emitting semiconductor laser chip and its fabrication method. Background Technology

[0002] EEL (Edge-Emitting Laser) is an abbreviation for semiconductor edge-emitting laser, a type of laser diode that uses compound semiconductor materials for photoelectric conversion. Its structure includes a quantum well emitting region, a P-type doped region, and an N-type doped region. Classified by application, it mainly includes high-speed lasers for optical communication and high-power lasers for industrial processing. Specific applications of high-power EELs include industrial cutting and welding, medical aesthetics, and lidar detection, generally based on indium gallium arsenide / gallium arsenide material systems.

[0003] To meet the output requirements of the laser, a coating needs to be deposited on the end face of the EEL (Electronic Electron Laser) in the emission direction. This coating forms a mirror at the interface between the semiconductor material and air, creating a resonant cavity. The coating material is typically silicon oxynitride (SiO2). However, before the end face coating step in high-power edge-emitting laser chips, the exposed aluminum material at the end face is highly susceptible to reacting with oxygen in the air to form oxides. Furthermore, the end face is a location of heat accumulation and is prone to damage, leading to chip failure. Traditionally, the selection of the coating material system and the control of the coating material growth conditions are used to create a near-perfect end face to reduce end face failure during device operation. However, this approach has limited effectiveness; end face damage (COMD: Catastrophic Optical Mirror Damage) remains the most significant failure mode in high-power edge-emitting lasers and a major obstacle to increasing the power of high-power EELs and transitioning them from experimental to mass production. Summary of the Invention

[0004] The purpose of this invention is to provide a high-power side-emitting semiconductor laser chip and its fabrication method, which can at least solve some of the defects in the prior art.

[0005] To achieve the above objectives, embodiments of the present invention provide the following technical solution: a method for fabricating a high-power side-emitting semiconductor laser chip, comprising the following steps:

[0006] S1, epitaxial growth of the laser structure;

[0007] S2, a mask is formed on the surface of the epitaxially grown wafer, and an etching pattern is formed on the mask, the pattern having etching points;

[0008] S3, a trench is formed at the etching point in the depth direction of the wafer;

[0009] S4, Remove the oxide layer in the trench;

[0010] S5, an etching barrier material is grown on the trench wall until it covers the upper surface of the wafer;

[0011] S6, continue with subsequent manufacturing to obtain the chip.

[0012] Furthermore, after the etch barrier material is grown, a protective crystal material is grown on the etch barrier material to fill the trench and overflow onto the etch barrier material on the upper surface of the wafer.

[0013] Next, photoresist is used to protect the protective crystal material directly above the trench, and the protective crystal material above the upper surface of the wafer is etched to the etch barrier material. The etch barrier material on the upper surface of the wafer is then etched to the upper surface of the wafer. After removing the photoresist, subsequent fabrication is performed to obtain the chip.

[0014] Furthermore, both the etching of the etching barrier material and the etching of the protective crystal material are performed using wet etching.

[0015] Furthermore, in step S3, the trench is formed by dry etching.

[0016] Furthermore, in step S2, there are multiple etching points, and a chip is formed by cutting along the groove formed by two adjacent etching points.

[0017] Furthermore, the length of the mask is the same as the length of the chip.

[0018] Furthermore, electrodes are fabricated using photolithography, sputtering, resist stripping, backside thinning, and high-temperature annealing processes.

[0019] Furthermore, the etching point is located on the end face of the chip, and the width of the etching point is controlled between 60 and 80 μm.

[0020] This invention provides another technical solution: a high-power side-emitting semiconductor laser chip, which is prepared by the above-described method for preparing a high-power side-emitting semiconductor laser chip.

[0021] Compared with the prior art, the beneficial effects of the present invention are: for high-power side-emitting semiconductor laser chips, after in-situ etching to remove the oxide layer, a protective material is pre-grown on the chip cutting end face to prevent the aluminum-containing material on the end face from being exposed and oxidized, thereby avoiding end face damage; the protective material can be an etching barrier material, or a combination of an etching barrier material and a protective crystal material. Attached Figure Description

[0022] Figure 1 A wafer cross-sectional view of a high-power side-emitting semiconductor laser chip provided in an embodiment of the present invention;

[0023] Figure 2 In order to be in Figure 1 A schematic diagram of forming a mask on a wafer based on the above.

[0024] Figure 3 In order to be in Figure 2 A schematic diagram showing the formation of grooves at the etching points based on the above.

[0025] Figure 4 In order to be in Figure 3 A schematic diagram of removing the mask based on the above.

[0026] Figure 5 In order to be in Figure 4 A schematic diagram showing the removal of the oxide layer on the basis of the above.

[0027] Figure 6 In order to be in Figure 5 A schematic diagram of the growth of an etching barrier material based on the above.

[0028] Figure 7 In order to be in Figure 6 A schematic diagram of growing protective crystal materials based on the above;

[0029] Figure 8 In order to be in Figure 7 A schematic diagram showing the application of photoresist to protect the location of the etched trenches;

[0030] Figure 9 In order to be in Figure 8 A schematic diagram of etching to protect the crystal material;

[0031] Figure 10 In order to be in Figure 9 A schematic diagram of an etching barrier material based on the above.

[0032] Figure 11 In order to be in Figure 10 A schematic diagram with the photoresist removed from the original image;

[0033] Figure 12 In order to be in Figure 11 Based on this, a schematic diagram of the p-electrode and n-electrode is constructed;

[0034] Figure 13 In order to be in Figure 12 A schematic diagram showing the chip formed by cutting along the groove based on the above.

[0035] In the attached figures: 1-substrate; 2-N-type doped region; 3-quantum well; 4-P-type doped region; 5-metal contact layer; 6-mask; 7-etching point; 8-trench; 9-oxide layer; 10-etch barrier material; 11-protective crystal material; 12-photoresist; 13-n electrode; 14-p electrode. Detailed Implementation

[0036] 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.

[0037] Please see Figures 1 to 13 This invention provides a method for fabricating a high-power edge-emitting semiconductor laser chip, comprising the following steps: S1, epitaxial growth of the laser structure; S2, forming a mask 6 on the surface of the epitaxially grown wafer, and forming an etching pattern on the mask 6, the pattern having etching points 7; S3, etching trenches 8 at the etching points 7 in the depth direction of the wafer; S4, removing the oxide layer 9 in the trenches 8; S5, growing an etching barrier material on the trench walls of the trenches 8 until it covers the upper surface of the wafer; S6, continuing subsequent fabrication to obtain the chip. For high-power edge-emitting semiconductor laser chips, after in-situ etching to remove the oxide layer 9, a protective material is pre-grown on the chip cutting end face to prevent the aluminum-containing material on the end face from being exposed and oxidized, thereby avoiding end face damage. Specifically, the aluminum-containing material can be re-grown in the trenches to prevent re-oxidation, and a re-growth process can be used.

[0038] from Figures 1 to 13 These are all the consecutive steps of this preparation method, which are described below in conjunction with... Figures 1 to 13 The following is a detailed description of this embodiment.

[0039] like Figure 1 (Wafer cross-section diagram) Epitaxial growth of N-type doped region 2, quantum well 3 (quantum well active region), P-type doped region 4, and metal contact layer 5 is performed on substrate 1. Wafer growth is typically performed in an MOCVD epitaxial growth furnace. Substrate 1 can be a gallium arsenide substrate, N-type doped region 2 can be n-AlGaAs, P-type doped region 4 can be p-AlGaAs, and metal contact layer 5 is used for ohmic contacts.

[0040] like Figure 2The wafer is removed from the growth furnace, and a silicon nitride mask 6 is formed on the wafer surface by photolithography. The etching points 7 of the mask are approximately 60-80 micrometers, serving as the end face positions of the EEL chip. The length protected by the mask 6 is determined by the final required chip length. The mask material is either carbon oxide or silicon nitride, which is used to define the etching pattern and also serves as the non-growth area for region-selective growth.

[0041] like Figure 3 The trenches 8 are formed by dry etching (ICP-RIE). Since the epitaxial material contains Al, the material at the trenches 8 will have an oxide layer 9 when exposed to air.

[0042] like Figure 4 Remove the etching mask used for dry etching 6.

[0043] like Figure 5 The wafer is then placed back into the growth furnace for in-situ etching to remove the oxide layer 9, thereby ensuring the quality of the regrowth.

[0044] like Figure 6 A layer of etching barrier material 10 is grown in an epitaxial growth furnace.

[0045] like Figure 7 In the epitaxial growth furnace, the end-face protected crystal material 11 (excluding aluminum material, such as GaAs) is grown and regrown to fill the etched trenches 8.

[0046] like Figure 8 Photolithography is used to protect the location of the etched trenches 8 with photoresist 12.

[0047] like Figure 9 The wet etching process for regrowing GaAs material will stop at the etching barrier material 10.

[0048] like Figure 10 , Figure 10 The etching barrier material 10 is removed by wet etching, and the etching process will stop at the epitaxial material of the metal contact layer 5.

[0049] like Figure 11 Remove photoresist 12.

[0050] like Figure 12 The process involves fabricating the front p electrode 14 and the back n electrode 13, including photolithography, sputtering, resist stripping, back thinning, and high-temperature annealing.

[0051] like Figure 13 The chip is cut along the groove formed by the regeneration process to complete the chip manufacturing process. There are multiple etching points 7, and a chip is formed by cutting along the groove 8 formed by two adjacent etching points 7.

[0052] Please see Figure 13 This invention also provides a high-power edge-emitting semiconductor laser chip, fabricated using the aforementioned method. This chip incorporates an etching barrier material and a protective crystal material, preventing the exposed aluminum-containing material on the end face from being oxidized and thus avoiding end-face damage.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a high-power side-emitting semiconductor laser chip, characterized in that, Includes the following steps: S1, epitaxial growth of the laser structure; S2, a mask is formed on the surface of the epitaxially grown wafer, and an etching pattern is formed on the mask, the pattern having etching points; S3, a trench is formed at the etching point in the depth direction of the wafer; S4, Remove the oxide layer in the trench; S5, an etching barrier material is grown on the trench wall until it covers the upper surface of the wafer; S6, continue with subsequent manufacturing to obtain the chip. After the etch stop material is grown, a protective crystal material is grown on the etch stop material to fill the trench and overflow onto the etch stop material on the upper surface of the wafer. Then, photoresist is used to protect the protective crystal material directly above the trench, and the protective crystal material above the upper surface of the wafer is etched onto the etch stop material. The etch stop material on the upper surface of the wafer is etched onto the upper surface of the wafer, and then the photoresist is removed before subsequent fabrication to obtain the chip.

2. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: Both the etching of the etching barrier material and the etching of the protective crystal material are performed using wet etching.

3. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: In step S3, the trench is formed by dry etching.

4. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: In step S2, there are multiple etching points, and a chip is formed by cutting along the groove formed by two adjacent etching points.

5. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: The length of the mask is the same as the length of the chip.

6. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: Electrodes are fabricated using photolithography, sputtering, resist stripping, backside thinning, and high-temperature annealing.

7. The method for fabricating a high-power side-emitting semiconductor laser chip as described in claim 1, characterized in that: The etching point is the end face position of the chip, and the width of the etching point is controlled between 60 and 80 μm.

8. A high-power side-emitting semiconductor laser chip, characterized in that: It is prepared by the method for fabricating a high-power side-emitting semiconductor laser chip as described in any one of claims 1-7.

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