A 640 nm semiconductor laser device with double-well narrow-barrier and a preparation method thereof

Abstract

This invention relates to a 640nm semiconductor laser device with a double-well narrow barrier and its fabrication method, belonging to the field of optoelectronic technology. From bottom to top, it includes a GaAs substrate, a GaAs buffer layer, a lower confinement layer, a lower waveguide layer one, a lower waveguide layer two, a quantum well one, a barrier layer, a quantum well two, an upper waveguide layer one, an upper waveguide layer two, an upper confinement layer, and (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P transition layer, Ga 0.5 In 0.5 The invention employs a P-transition layer and a GaAs cap layer, with a barrier layer thickness of less than 3.5 nm. Through a double-well compressive strain structure design, the invention improves the conduction bandgap difference and suppresses carrier overflow; through a narrow barrier structure design, it enhances the pulse operating response speed; and by reducing N-side doping, it reduces absorption loss and improves photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention relates to a 640nm semiconductor laser device with a double-well narrow barrier and its fabrication method, belonging to the field of optoelectronic technology. Background Technology

[0002] 640nm semiconductor lasers, as red light sources, are widely used in laser display, laser projection and other fields, bringing more realistic colors and a more immersive eye-friendly sensory experience. With the increasing demand from consumers for large-screen and multi-scenario applications, laser projection has entered a critical period of development and has huge development potential in terms of consumer groups and application scenarios.

[0003] Higher laser output power translates to higher optical efficiency and a brighter visual appearance. However, with the shortening wavelength of AlGaInP-based 640nm semiconductor lasers, the conduction band gap between the tensile strained GaInP and AlGaInP confinement layers becomes smaller, leading to severe carrier overflow and making high-temperature operation difficult. Simultaneously, the lower photoelectric conversion efficiency results in increased active region temperature, degrading the device's photoelectric performance and hindering continuous high-power output at high temperatures. Increasing the number of quantum wells can effectively improve the optical confinement factor and high-temperature operating characteristics, but it increases the pulse response time, affecting overall performance. Therefore, improving both high-temperature characteristics and pulse response time would facilitate further applications of 640nm lasers in the display field.

[0004] The literature *Optoelectronics and Lasers*, 22(9), 2011, 1326-1331, compared the changes in -IV characteristics, light intensity, and internal quantum efficiency (IQE) of light-emitting diodes (LEDs) with different barrier heights, barrier widths, and well widths under different conditions. It pointed out that when the barrier width is sufficiently small, the distance that charge carriers travel through the quantum well structure is shortened, resulting in a resonant tunneling effect. As the transmission coefficient increases, the probability of carrier recombination also increases. However, the surface-emitting structure of LEDs differs from that of edge-emitting semiconductor lasers (LDs) in terms of structural design and operating characteristics, and therefore there are no applications in this area.

[0005] The literature "Laser & Optoelectronics Progress", 56(18), 2019, 180001:1-12 summarizes the current research status and progress of red semiconductor lasers used for laser displays at home and abroad. However, quantum wells using tensile strained GaInP have small conduction band gap differences and poor carrier suppression capabilities. Wide well structures can improve high-temperature operating characteristics, but it is difficult to use double well structures. Summary of the Invention

[0006] To address the above problems, this invention provides a 640nm semiconductor laser device with a double-well narrow barrier and a method for its fabrication.

[0007] (1) A double-well structure is adopted to improve the light confinement factor and improve the high-temperature operating characteristics;

[0008] (2) Reduce the barrier layer thickness, increase the transmission coefficient, increase the carrier recombination probability, and shorten the pulse response time;

[0009] (3) By using compressive strain GaInP, the thickness of the quantum well is reduced, and a 640nm lasing wavelength is achieved. The compressive strain structure helps to improve the conduction band gap difference, suppress carrier escape, and enhance the electron confinement capability.

[0010] The technical solution of the present invention is as follows:

[0011] A 640nm semiconductor laser device with a double-well narrow barrier comprises, from bottom to top, a GaAs substrate, a GaAs buffer layer, and an Al layer. 0.5 In 0.5 P-lower confinement layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer 1, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-waveguide layer II, Ga 1-x3 In x3 P-quantum well I, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P barrier layer, Ga 1-x5 In x5 p-quantum well II, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper waveguide layer 1, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer II, Al 0.5 In 0.5 P upper confinement layer, (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P transition layer, Ga 0.5 In 0.5 P transition layer and GaAs cap layer;

[0012] Wherein, 0.65≤x1≤0.75, 0.4≤y1≤0.6; 0.3≤x2≤0.6, 0.4≤y2≤0.6; 0.35≤x3≤0.5; 0.3≤x4≤0.6, 0.55≤y3≤0.65; 0.35≤x5≤0.5; 0.3≤x6≤0.6, 0.4≤y4≤0.6; 0.65≤x7≤0.75, 0.4≤y5≤0.6;

[0013] Among them, the double GaInP quantum well improves high-temperature operating characteristics; the compressive strain quantum well increases the conduction band gap difference, suppresses carrier overflow, and improves high-temperature operating characteristics; the (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-narrow barrier structure (thickness less than 3.5 nm) increases the probability of carrier recombination and reduces the pulse response time.

[0014] A method for fabricating the above-mentioned double-well narrow-barrier 640nm semiconductor laser device includes the following steps:

[0015] S1. Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on the GaAs substrate.

[0016] S2. Slowly reduce the temperature to 680±10℃, with a cooling rate not exceeding 30℃ / min, and continue to introduce TMGa and AsH3 to grow a GaAs buffer layer on the GaAs substrate. The purpose is to prevent defects from spreading from the substrate into the confinement layer, provide a fresh growth interface, and improve the material growth quality.

[0017] S3. The temperature is maintained at 680±10℃. Growth is stopped on the GaAs buffer layer. PH3 is introduced to stop the growth by stopping the V group source (100% AsH3) and the III group source (TMGa). The stoppage lasts for 3 to 30 seconds, exhausting the As atoms in the reaction chamber and avoiding the formation of AsP complex, which would affect the interface lattice matching.

[0018] S4. Gradually reduce the temperature to 700±10℃, with a heating rate not exceeding 60℃ / min, and introduce TMAl, TMIn, and PH3 to grow n-type Al on the GaAs buffer layer. 0.5 In 0.5 The lower confinement layer (P) restricts the optical field in the active region;

[0019] S5. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3 into Al. 0.5 In 0.5 Growth on the P-limiting layer (Al) x1 Ga1-x1 ) y1 In 1-y1 The first waveguide layer under P is grown with high Al composition AlGaInP to improve carrier suppression capability and also serves as a transition layer to reduce the interaction between the confinement layer and (Al). x2 Ga 1-x2 ) y2 In 1-y2 The bandgap difference between the two waveguide layers under P reduces the voltage drop and decreases the voltage.

[0020] S6. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3. In (Al... x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer grown on top (Al) x2 Ga 1-x2 ) y2 In 1-y2 The second waveguide layer under P provides photoelectric confinement for the quantum well;

[0021] S7. Gradually reduce the temperature to 640±10℃, introduce TMI, TMGa, and PH3, and in (Al) x2 Ga 1-x2 ) y2 In 1-y2 Ga is grown on the lower waveguide layer of P. 1-x3 In x3 P-quantum well 1;

[0022] S8. The temperature is maintained at 640±10℃, and TMAl, TMIn, TMGa and PH3 are introduced. 1-x3 In x3 P-quantum well growth (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer;

[0023] S9, maintain the temperature at 640±10℃, introduce TMI, TMGa and PH3, in (Al) x4 Ga 1-x4 ) y3 In 1-y3 Ga grows on the P barrier layer 1-x5 In x5 P-quantum well two;

[0024] S10, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Ga 1-x5 In x5 P-quantum well double growth (Al) x6 Ga1-x6 ) y4 In 1-y4 Waveguide layer 1 on P provides photoelectric confinement for the quantum well;

[0025] S11, maintain the temperature at 700±10℃, introduce TMAl, TMIn, TMGa and PH3, in (Al x6 Ga 1-x6 ) y4 In 1-y4 Waveguide layer grown on P (Al) x7 Ga 1-x7 ) y5 In 1-y5 Waveguide layer 2 on P is grown with high Al composition AlGaInP to improve carrier suppression capability and also serves as a transition layer to reduce the interaction between the confinement layer and (Al). x6 Ga 1-x6 ) y4 In 1-y4 The bandgap difference between waveguide layers P and P reduces voltage drop and decreases voltage.

[0026] S12, maintain the temperature at 700±10℃, introduce TMAl, TMIn and PH3, in (Al) x7 Ga 1-x7 ) y5 In 1-y5 p-type Al is grown on the upper waveguide layer of P. 0.5 In 0.5 A confinement layer on P restricts the optical field in the active region;

[0027] S13, the temperature is gradually reduced to 670±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on the confinement layer of P (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 The P-transition layer reduces the bandgap difference between the confinement layer and the cap layer, thus reducing the voltage.

[0028] S14, maintain the temperature at 670±10℃, introduce TMI, TMGa and PH3, in (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 Ga grows on the P transition layer 0.5 In 0.5 The P-transition layer reduces the bandgap difference between the confinement layer and the cap layer, thus reducing the voltage.

[0029] S15. The temperature is gradually reduced to 540±10℃, and the cooling rate does not exceed 40℃ / min. PH3 is continuously introduced to protect the growth interface and complete the cooling process.

[0030] S16. Maintain the temperature at 540±10℃ and continue to introduce TMGa and AsH3, in Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P transition layer to provide an ohmic alloy layer for subsequent processes.

[0031] Preferably, in step S2, the doping source of the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm³. 3 The thickness is 0.1-0.3 μm; preferably, the GaAs buffer layer has a thickness of 0.2 μm and a doping concentration of 2E18 atoms / cm³. 3 ;

[0032] In step S4, n-type Al 0.5 In 0.5 The doping source for the p-confined layer is Si₂H₆, with a doping concentration of 2E¹⁷-1E¹⁸ atoms / cm². 3 The thickness is 0.8-3 μm; preferably, n-type Al 0.5 In 0.5 The p-confinement layer has a thickness of 1.5 μm and a doping concentration of 5E17 atoms / cm². 3 .

[0033] Preferably, in step S5, (Al) x1 Ga 1-x1 ) y1 In 1-y1 The doping source for waveguide layer 1 under P is Si2H6, with a thickness of 10-50 nm and a doping concentration of 7E16-4E17 atoms / cm. 3 0.65≤x1≤0.75, 0.4≤y1≤0.6; preferably, x1=0.7, y1=0.5, thickness is 20nm, and doping concentration is 1E17 atoms / cm. 3 ;

[0034] In step S6, (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of the second waveguide layer under P is 50-150nm, unintentionally doped, with 0.3≤x2≤0.6 and 0.4≤y2≤0.6; preferably, x2=0.5, y2=0.5, and the thickness is 100nm.

[0035] Preferably, in step S7, Ga 1-x3 In x3The thickness of the P quantum well is 3-4.5 nm, unintentionally doped, with 0.35 ≤ x3 ≤ 0.5; preferably, x3 = 0.44, and the thickness is 3.7 nm, achieving a PL lasing wavelength of 627 nm in the photoluminescence spectrometer.

[0036] Preferably, in step S8, (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P barrier layer is 2-5 nm, unintentionally doped, with 0.3 ≤ x4 ≤ 0.6 and 0.55 ≤ y3 ≤ 0.65; preferably, x4 = 0.5, y3 = 0.43, and a thickness of 3 nm. The lattice constant is less than that of GaAs. The material is subjected to tensile stress, and the tensile strain of the barrier layer is used to improve the conduction band gap difference.

[0037] Preferably, in step S9, Ga 1-x5 In x5 The thickness of the P-quantum well 2 is 3-4.5 nm, unintentionally doped, with 0.35 ≤ x5 ≤ 0.5; preferably, x5 = 0.44, and the thickness is 3.7 nm, achieving a PL lasing wavelength of 627 nm;

[0038] Furthermore, in step S10, (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of waveguide layer 1 on P is 50-150nm, unintentionally doped, with 0.3≤x6≤0.6 and 0.4≤y4≤0.6; preferably, x6=0.5, y4=0.5, and the thickness is 100nm.

[0039] Preferably, in step S11, (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of waveguide layer 2 on P is 10-50 nm, and the doping concentration is 7E16-4E17 atoms / cm. 3 0.65≤x7≤0.75, 0.4≤y5≤0.6; preferably, x7=0.7, y5=0.5, thickness is 20nm, and doping concentration is 2E17 atoms / cm. 3 .

[0040] Preferably, in step S12, p-type Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 5E¹⁷–1.5E¹⁸ atoms / cm². 3 The thickness is 0.5-1.5 μm; preferably, p-type Al 0.5 In 0.5The p-confinement layer has a thickness of 0.9 μm and a doping concentration of 8E17 atoms / cm². 3 ;

[0041] In step S13, (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 The doping source for the P transition layer is Cp₂Mg, with a doping concentration of 1E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 10-50 nm; preferably, the thickness is 20 nm, and the doping concentration is 2E18 atoms / cm. 3 .

[0042] Preferably, in step S14, Ga 0.5 In 0.5 The doping source for the P transition layer is Cp₂Mg, with a doping concentration of 1E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 10-50 nm; preferably, the thickness is 20 nm, and the doping concentration is 2E18 atoms / cm. 3 ;

[0043] In step S16, the thickness of the cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm³. 3 Preferably, the thickness is 0.3 μm and the doping concentration is 7E19 atoms / cm². 3 .

[0044] The MOCVD equipment and other technologies used in the method of this invention are all existing technologies.

[0045] TMGa, TMIn, TMAl, PH3, and AsH3 are all raw materials for MOCVD epitaxial growth, while Si2H6, Cp2Mg, CBr4, and DEZn are all dopant sources for epitaxial growth.

[0046] For any details not covered in this invention, please refer to the prior art.

[0047] The beneficial effects of this invention are as follows:

[0048] (1) The quantum well lattice constant is greater than that of the GaAs substrate. The material is subjected to compressive strain. This invention utilizes the compressive strain GaInP quantum well, where light holes decrease and heavy holes increase, increasing the conduction band gap difference with the confinement layer, thereby improving the conduction band gap difference and increasing the carrier suppression capability.

[0049] (2) The present invention utilizes a double-well structure to increase the overlap between the optical field and the quantum well, improve the optical confinement factor, and enhance the high-temperature working characteristics.

[0050] (3) The present invention reduces the barrier layer thickness, narrow barrier structure design, improves the transmission coefficient, increases the carrier recombination probability, shortens the pulse response time and improves the pulse response speed.

[0051] (4) The present invention utilizes a low-doping design of the N-confined layer to reduce absorption loss and improve photoelectric conversion efficiency. Attached Figure Description

[0052] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0053] Figure 1 It is a conventional structure;

[0054] Figure 2 This is the laser structure of the present invention;

[0055] Among them, 1-GaAs substrate, 2-GaAs buffer layer, 3-Al 0.5 In 0.5 P-confinement layer, 4-(Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer 1, 5-(Al) x2 Ga 1-x2 ) y2 In 1-y2 P-waveguide layer II, 6-Ga 1-x3 In x3 p-quantum well 1, 7-(Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer, 8-Ga 1-x5 In x5 p-quantum well II, 9-(Al) x6 Ga 1-x6 ) y4 In 1-y4 P-waveguide layer 1, 10-(Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer II, 11-Al 0.5 In 0.5 P upper confinement layer, 12-(Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P transition layer, 13-Ga 0.5 In 0.5 P transition layer, 14-GaAs cap layer. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. However, this is not the only description; all aspects not described in detail herein are based on conventional techniques in the art.

[0057] Example 1

[0058] A 640nm semiconductor laser device with a double-well narrow barrier, such as Figure 2 As shown, from bottom to top, it includes a GaAs substrate 1, a GaAs buffer layer 2, and an Al layer 3. 0.5 In 0.5 P-lower confinement layer 3, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-lower waveguide layer 14, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-waveguide layer 2, Ga 1-x3 In x3 p-quantum well-6, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer 7, Ga 1-x5 In x5 P-quantum well 28, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper waveguide layer 19, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer 2 10, Al 0.5 In 0.5 P upper confinement layer 11, (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P-transition layer 12, Ga 0.5 In 0.5 P transition layer 13 and GaAs cap layer 14;

[0059] Wherein, 0.65≤x1≤0.75, 0.4≤y1≤0.6; 0.3≤x2≤0.6, 0.4≤y2≤0.6; 0.35≤x3≤0.5; 0.3≤x4≤0.6, 0.55≤y3≤0.65; 0.35≤x5≤0.5; 0.3≤x6≤0.6, 0.4≤y4≤0.6; 0.65≤x7≤0.75, 0.4≤y5≤0.6;

[0060] Among them, the double GaInP quantum well improves high-temperature operating characteristics; the compressive strain quantum well increases the conduction band gap difference, suppresses carrier overflow, and improves high-temperature operating characteristics; the (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-narrow barrier structure (thickness less than 3.5 nm) increases the probability of carrier recombination and reduces the pulse response time.

[0061] Example 2

[0062] A method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier includes the following steps:

[0063] S1. Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on the GaAs substrate.

[0064] S2. Slowly reduce the temperature to 680±10℃, with a cooling rate not exceeding 30℃ / min, and continue to introduce TMGa and AsH3 to grow a GaAs buffer layer on the GaAs substrate. The purpose is to prevent defects from spreading from the substrate into the confinement layer, provide a fresh growth interface, and improve the material growth quality.

[0065] The doping source for the GaAs buffer layer is Si₂H₆, the thickness of the GaAs buffer layer is 0.2 μm, and the doping concentration is 2E¹⁸ atoms / cm². 3 ;

[0066] S3. The temperature is maintained at 680±10℃. Growth is stopped on the GaAs buffer layer. PH3 is introduced to stop the growth by stopping the V group source (100% AsH3) and the III group source (TMGa). The stoppage lasts for 3 to 30 seconds, exhausting the As atoms in the reaction chamber and avoiding the formation of AsP complex, which would affect the interface lattice matching.

[0067] S4. Gradually reduce the temperature to 700±10℃, with a heating rate not exceeding 60℃ / min, and introduce TMAl, TMIn, and PH3 to grow n-type Al on the GaAs buffer layer. 0.5 In 0.5 The lower confinement layer (P) restricts the optical field in the active region;

[0068] n-type Al 0.5 In 0.5 The doping source for the p-confined layer is Si₂H₆, with a thickness of 1.5 μm and a doping concentration of 5E¹⁷ atoms / cm². 3 ;

[0069] S5. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3 into Al. 0.5 In 0.5 Growth on the P-limiting layer (Al) x1 Ga 1-x1 ) y1 In 1-y1 The first waveguide layer under P is grown with high Al composition AlGaInP to improve carrier suppression capability and also serves as a transition layer to reduce the interaction between the confinement layer and (Al). x2 Ga 1-x2 ) y2 In 1-y2 The bandgap difference between the two waveguide layers under P reduces the voltage drop and decreases the voltage.

[0070] (Al x1 Ga 1-x1 ) y1 In 1-y1 The doping source for waveguide layer 1 under P is Si₂H₆, x₁ = 0.7, y₁ = 0.5, the thickness is 20 nm, and the doping concentration is 1E¹⁷ atoms / cm². 3 ;

[0071] S6. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3. In (Al... x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer grown on top (Al) x2 Ga 1-x2 ) y2 In 1-y2 The second waveguide layer under P provides photoelectric confinement for the quantum well;

[0072] (Al x2 Ga 1-x2 ) y2 In 1-y2 The lower waveguide layer P is unintentionally doped, with x2 = 0.5, y2 = 0.5, and a thickness of 100 nm;

[0073] S7. Gradually reduce the temperature to 640±10℃, introduce TMI, TMGa, and PH3, and in (Al) x2 Ga 1-x2 ) y2 In 1-y2Ga is grown on the lower waveguide layer of P. 1-x3 In x3 P-quantum well 1;

[0074] Ga 1-x3 In x3 A P-quantum well with unintentional doping, x3 = 0.44, and a thickness of 3.7 nm, achieves a PL lasing wavelength of 627 nm in a photoluminescence spectrometer;

[0075] S8. The temperature is maintained at 640±10℃, and TMAl, TMIn, TMGa and PH3 are introduced. 1-x3 In x3 P-quantum well growth (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer;

[0076] (Al x4 Ga 1-x4 ) y3 In 1-y3 The P-barrier layer is unintentionally doped, with x4 = 0.5, y3 = 0.43, and a thickness of 3 nm. Its lattice constant is less than that of GaAs. The material is subjected to tensile stress, and the tensile strain of the barrier layer is used to improve the conduction band gap difference.

[0077] S9, maintain the temperature at 640±10℃, introduce TMI, TMGa and PH3, in (Al) x4 Ga 1-x4 ) y3 In 1-y3 Ga grows on the P barrier layer 1-x5 In x5 P-quantum well two;

[0078] Ga 1-x5 In x5 The P-quantum well is unintentionally doped with x5 = 0.44 and has a thickness of 3.7 nm, achieving a PL lasing wavelength of 627 nm.

[0079] S10, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Ga 1-x5 In x5 P-quantum well double growth (Al) x6 Ga 1-x6 ) y4 In 1-y4 Waveguide layer 1 on P provides photoelectric confinement for the quantum well;

[0080] (Al x6 Ga 1-x6 ) y4 In 1-y4The waveguide layer on P is unintentionally doped, with x6 = 0.5, y4 = 0.5, and a thickness of 100 nm;

[0081] S11, maintain the temperature at 700±10℃, introduce TMAl, TMIn, TMGa and PH3, in (Al x6 Ga 1-x6 ) y4 In 1-y4 Waveguide layer grown on P (Al) x7 Ga 1-x7 ) y5 In 1-y5 Waveguide layer 2 on P is grown with high Al composition AlGaInP to improve carrier suppression capability and also serves as a transition layer to reduce the interaction between the confinement layer and (Al). x6 Ga 1-x6 ) y4 In 1-y4 The bandgap difference between waveguide layers P and P reduces voltage drop and decreases voltage.

[0082] (Al x7 Ga 1-x7 ) y5 In 1-y5 In waveguide layer 2 on P, x7 = 0.7, y5 = 0.5, the thickness is 20 nm, and the doping concentration is 2E17 atoms / cm². 3

[0083] S12, maintain the temperature at 700±10℃, introduce TMAl, TMIn and PH3, in (Al) x7 Ga 1-x7 ) y5 In 1-y5 p-type Al is grown on the upper waveguide layer of P. 0.5 In 0.5 A confinement layer on P restricts the optical field in the active region;

[0084] p-type Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a thickness of 0.9 μm and a doping concentration of 8E¹⁷ atoms / cm². 3 ;

[0085] S13, the temperature is gradually reduced to 670±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on the confinement layer of P (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 The P-transition layer reduces the bandgap difference between the confinement layer and the cap layer, thus reducing the voltage.

[0086] (Al 0.5 Ga 0.5 ) 0.5 In 0.5 The dopant source for the P-transition layer is Cp₂Mg, with a thickness of 20 nm and a doping concentration of 2E¹⁸ atoms / cm². 3 ;

[0087] S14, maintain the temperature at 670±10℃, introduce TMI, TMGa and PH3, in (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 Ga grows on the P transition layer 0.5 In 0.5 The P-transition layer reduces the bandgap difference between the confinement layer and the cap layer, thus reducing the voltage.

[0088] Ga 0.5 In 0.5 The dopant source for the P-transition layer is Cp₂Mg, with a thickness of 20 nm and a doping concentration of 2E¹⁸ atoms / cm². 3 ;

[0089] S15. The temperature is gradually reduced to 540±10℃, and the cooling rate does not exceed 40℃ / min. PH3 is continuously introduced to protect the growth interface and complete the cooling process.

[0090] S16. Maintain the temperature at 540±10℃ and continue to introduce TMGa and AsH3, in Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P transition layer to provide an ohmic alloy layer for subsequent processes.

[0091] The cap layer has a thickness of 0.3 μm and a doping concentration of 7E19 atoms / cm². 3 .

[0092] Comparative Example 1

[0093] A 640nm semiconductor laser device, compared to Example 1, does not have (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer 7 and Ga 1-x5 In x5 P-quantum well 28, with other structures the same as in the embodiment.

[0094] Table 1 shows the bar strip test data for the laser devices of Comparative Example 1 and Embodiment 1 of the present invention, with a cavity length of 1500 μm, a stripe width of 110 μm, and a duty cycle of 1% without coating. As can be seen from Table 1, the voltage of the laser device of the present invention is slightly higher than that of the conventional structure (Comparative Example 1). This may be due to the increased voltage caused by the addition of the well-barrier interface, and the increased threshold current caused by the double well. However, the present invention suppresses carrier overflow, improves the optical confinement factor, increases the slope efficiency, improves the peak power, and significantly increases the photoelectric conversion efficiency.

[0095] Table 1: Test data for Comparative Example 1 and Example 1

[0096] category Threshold current A Operating voltage V Slope efficiency W / A Peak power W@1.5A Comparative Example 1 0.48 2.12 0.48 0.48 Example 1 0.54 2.2 0.59 0.56

[0097] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A 640nm semiconductor laser device with a double-well narrow barrier, characterized in that, From bottom to top, it includes a GaAs substrate, a GaAs buffer layer, and an Al layer. 0.5 In 0.5 P-lower confinement layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer 1, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-waveguide layer II, Ga 1-x3 In x3 p-quantum well 1, (Al) x4 Ga 1-x4 ) y3 In 1-y3 P barrier layer, Ga 1-x5 In x5 p-quantum well II, (Al) x6 Ga 1-x6 ) y4 In 1-y4 P upper waveguide layer 1, (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer II, Al 0.5 In 0.5 P upper confinement layer, (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P transition layer, Ga 0.5 In 0.5 P transition layer and GaAs cap layer; Wherein, 0.65≤x1≤0.75, 0.4≤y1≤0.6; 0.3≤x2≤0.6, 0.4≤y2≤0.6; 0.35≤x3≤0.5; 0.3≤x4≤0.6, 0.55≤y3≤0.65; 0.35≤x5≤0.5; 0.3≤x6≤0.6, 0.4≤y4≤0.6; 0.65≤x7≤0.75, 0.4≤y5≤0.6; (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer is less than 3.5 nm.

2. A method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier as described in claim 1, characterized in that, Includes the following steps: S1. Place the GaAs substrate in the growth chamber of the MOCVD equipment, heat the H2 environment to 720±10℃ for baking, and introduce AsH3 to perform surface heat treatment on the GaAs substrate. S2. Slowly reduce the temperature to 680±10℃, with a cooling rate not exceeding 30℃ / min, and continue to introduce TMGa and AsH3 to grow a GaAs buffer layer on the GaAs substrate. S3. The temperature is maintained at 680±10℃. Growth is stopped on the GaAs buffer layer. PH3 is introduced to stop the growth by stopping the V group source and the III group source. The stoppage lasts for 3 to 30 seconds, and the As atoms in the reaction chamber are exhausted. S4. Gradually reduce the temperature to 700±10℃, with a heating rate not exceeding 60℃ / min, and introduce TMAl, TMIn, and PH3 to grow n-type Al on the GaAs buffer layer. 0.5 In 0.5 The lower confinement layer (P) restricts the optical field in the active region; S5. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3 into Al. 0.5 In 0.5 Growth on the P-limiting layer (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer 1; S6. Maintain the temperature at 700±10℃, and introduce TMAl, TMIn, TMGa, and PH3. In (Al... x1 Ga 1-x1 ) y1 In 1-y1 P-waveguide layer grown on top (Al) x2 Ga 1-x2 ) y2 In 1-y2 The second waveguide layer under P provides photoelectric confinement for the quantum well; S7. Gradually reduce the temperature to 640±10℃, introduce TMI, TMGa, and PH3, and in (Al) x2 Ga 1-x2 ) y2 In 1-y2 Ga is grown on the lower waveguide layer of P. 1-x3 In x3 P-quantum well 1; S8. The temperature is maintained at 640±10℃, and TMAl, TMIn, TMGa and PH3 are introduced. 1-x3 In x3 P-quantum well growth (Al) x4 Ga 1-x4 ) y3 In 1-y3 P-barrier layer; S9, maintain the temperature at 640±10℃, introduce TMI, TMGa and PH3, in (Al) x4 Ga 1-x4 ) y3 In 1-y3 Ga grows on the P barrier layer 1-x5 In x5 P-quantum well two; S10, the temperature is gradually reduced to 700±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Ga 1-x5 In x5 P-quantum well double growth (Al) x6 Ga 1-x6 ) y4 In 1-y4 Waveguide layer 1 on P provides photoelectric confinement for the quantum well; S11, maintain the temperature at 700±10℃, introduce TMAl, TMIn, TMGa and PH3, in (Al x6 Ga 1-x6 ) y4 In 1-y4 Waveguide layer grown on P (Al) x7 Ga 1-x7 ) y5 In 1-y5 P upper waveguide layer two; S12, maintain the temperature at 700±10℃, introduce TMAl, TMIn and PH3, in (Al) x7 Ga 1-x7 ) y5 In 1-y5 p-type Al is grown on the upper waveguide layer of P. 0.5 In 0.5 A confinement layer on P restricts the optical field in the active region; S13, the temperature is gradually reduced to 670±10℃, and TMAl, TMIn, TMGa and PH3 are introduced, in Al 0.5 In 0.5 Growth on the confinement layer of P (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 P transition layer S14, maintain the temperature at 670±10℃, introduce TMI, TMGa and PH3, in (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 Ga grows on the P transition layer 0.5 In 0.5 P-transition layer; S15. The temperature is gradually reduced to 540±10℃, and the cooling rate does not exceed 40℃ / min. PH3 is continuously introduced to protect the growth interface and complete the cooling process. S16. Maintain the temperature at 540±10℃ and continue to introduce TMGa and AsH3, in Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P transition layer to provide an ohmic alloy layer for subsequent processes.

3. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S2, the doping source for the GaAs buffer layer is Si2H6, and the doping concentration is 2E18-5E18 atoms / cm³. 3 The thickness is 0.1-0.3μm; In step S4, n-type Al 0.5 In 0.5 The doping source for the p-confined layer is Si₂H₆, with a doping concentration of 2E¹⁷-1E¹⁸ atoms / cm². 3 The thickness is 0.8-3μm.

4. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S5, (Al) x1 Ga 1-x1 ) y1 In 1-y1 The doping source for waveguide layer 1 under P is Si2H6, with a thickness of 10-50 nm and a doping concentration of 7E16-4E17 atoms / cm. 3 , 0.65≤x1≤0.75, 0.4≤y1≤0.6; In step S6, (Al) x2 Ga 1-x2 ) y2 In 1-y2 The thickness of waveguide layer 2 under P is 50-150nm, unintentionally doped, with 0.3≤x2≤0.6 and 0.4≤y2≤0.

6.

5. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S7, Ga 1-x3 In x3 The thickness of the P-quantum well is 3-4.5 nm, unintentionally doped, with 0.35 ≤ x3 ≤ 0.

5.

6. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, (Al) x4 Ga 1-x4 ) y3 In 1-y3 The thickness of the P-barrier layer is 2-5 nm, unintentionally doped, with 0.3 ≤ x4 ≤ 0.6 and 0.55 ≤ y3 ≤ 0.

65.

7. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S9, Ga 1-x5 In x5 The thickness of the p-quantum well 2 is 3-4.5 nm, unintentionally doped, with 0.35 ≤ x5 ≤ 0.5; In step S10, (Al) x6 Ga 1-x6 ) y4 In 1-y4 The thickness of waveguide layer 1 on P is 50-150nm, unintentionally doped, with 0.3≤x6≤0.6 and 0.4≤y4≤0.

6.

8. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S11, (Al) x7 Ga 1-x7 ) y5 In 1-y5 The thickness of waveguide layer 2 on P is 10-50 nm, and the doping concentration is 7E16-4E17 atoms / cm. 3 , 0.65≤x7≤0.75, 0.4≤y5≤0.

6.

9. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S12, p-type Al 0.5 In 0.5 The doping source for the confinement layer on P is Cp₂Mg, with a doping concentration of 5E¹⁷–1.5E¹⁸ atoms / cm². 3 The thickness is 0.5-1.5μm; In step S13, (Al) 0.5 Ga 0.5 ) 0.5 In 0.5 The doping source for the P transition layer is Cp₂Mg, with a doping concentration of 1E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 10-50nm.

10. The method for fabricating a 640nm semiconductor laser device with a double-well narrow barrier according to claim 2, characterized in that, In step S14, Ga 0.5 In 0.5 The doping source for the P transition layer is Cp₂Mg, with a doping concentration of 1E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 10-50nm; In step S16, the thickness of the cap layer is 0.1-0.5 μm, the doping source is CBr4 or DEZn, and the doping concentration is 4E19-1E20 atoms / cm³. 3 .

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