An AlGaInP red light semiconductor laser device with improved light confinement factor and a preparation method thereof

Abstract

The application relates to an AlGaInP red light semiconductor laser device with improved light confinement factors and a preparation method thereof, belonging to the field of optoelectronic technology, and sequentially comprising a GaAs substrate, a GaAs buffer layer, a GaInP lower transition layer, a lower confinement layer one, a lower confinement layer two, a lower waveguide layer, a GaInAsP quantum well, an upper waveguide layer, an upper confinement layer one, an upper confinement layer two, a GaInP upper transition layer and a GaAs cap layer from bottom to top; through the design of asymmetric confinement layers and waveguide layers, the application realizes the light field offset to the N confinement layer, reduces the absorption loss and lowers the threshold current; through the insertion of high refractive index layers in the N and P confinement layers, the application concentrates the light field, improves the light confinement factor and lowers the threshold current; through the reduction of the doping concentration in the light field concentration area, the application reduces the absorption loss.

Description

TECHNICAL FIELD

[0001] The application relates to an AlGaInP red light semiconductor laser device with improved light confinement factor and a preparation method thereof, and belongs to the technical field of optoelectronics. BACKGROUND

[0002] The 785nm semiconductor laser is widely used in the application fields of laser printing, distance measurement, and sweeping robot, and with the development of artificial intelligence technology, the semiconductor laser has a greater development prospect in the digital field, and higher requirements are put forward for photoelectric conversion efficiency, reliability and other performances.

[0003] The 785nm semiconductor laser usually has two material systems of AlGaInP and AlGaAs, wherein the AlGaInP structure can adopt an aluminum-free active region, is slow in oxidation, has a low surface recombination rate, has a high cavity surface catastrophe threshold, can bear a higher optical power density, and is slow in cavity surface degradation rate and has an inhibitory effect on the climbing of dark line defects, and is slow in material internal degradation rate, which is beneficial to improving the working reliability. In order to reduce the threshold current and improve the photoelectric conversion efficiency, an asymmetric structure is usually adopted, so that the light field deviates to the n-type region and the light absorption in the p-type limiting layer is reduced.

[0004] Chinese patent document CN100574027C discloses an aluminum-free active region 808nm high-power quantum well laser with an asymmetric structure, which uses aluminum gallium indium phosphorus materials with different aluminum components as the lower limiting layer and the upper limiting layer, increases the light confinement factor of the P-type material region, reduces the leakage of light to the P-type material region, reduces the carrier light absorption loss of the high-doped region, improves the working efficiency of the laser, and at the same time, the structure improves the limiting effect of the active region on the carriers and reduces the leakage of the carriers, which is beneficial to the reduction of the threshold current. However, in this case, the spread of light in the limiting layer is not effectively inhibited, and after the light field deviates, the quantum well is deviated, which affects the light gain and increases the threshold current.

[0005] Semiconductor Science and Technology (Journal), Vol 33, 2008, 65-67, discloses that AlGaInP is used as the limiting layer, the band gap difference between the limiting layer and the active region is increased, which is beneficial to preventing the leakage of carriers and improving the photoelectric conversion efficiency of the laser, a large optical cavity structure is adopted, and the waveguide layer thickness is asymmetric, so that the light field deviates to the n-type region and the light absorption in the P-type limiting layer is reduced, and the photoelectric conversion efficiency of the laser is improved. Although the asymmetric component limiting layer and the asymmetric thickness waveguide layer are adopted to realize the deviation of the light field and reduce the absorption loss, the limiting of the light field in the limiting layer is not further reduced to reduce the threshold current. SUMMARY

[0006] To address the aforementioned issues, this invention proposes an AlGaInP red semiconductor laser device with improved optical confinement factor and its fabrication method. Through the design of an asymmetric confinement layer and waveguide layer, the optical field is shifted towards the N-confinement layer, reducing absorption loss and lowering the threshold current. Furthermore, by inserting a high-refractive-index layer into the N and P confinement layers, the optical field is concentrated, improving the optical confinement factor and reducing the threshold current. Finally, reducing the doping concentration in the concentrated optical field region further reduces absorption loss.

[0007] The present invention adopts the following technical solution:

[0008] An AlGaInP red semiconductor laser device with improved light confinement factor, comprising, from bottom to top, a GaAs substrate, a GaAs buffer layer, and a GaAs layer. 0.5 In 0.5 P-transition layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-lower confinement layer 1, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-lower confinement layer two, (Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, GaInAsP quantum well, (Al) x4 Ga 1-x4 ) y4 In 1-y4 P upper waveguide layer, (Al) x5 Ga 1-x5 ) y5 In 1-y5 P upper confinement layer one, (Al) x6 Ga 1-x6 ) y6 In 1-y6 P upper confinement layer 2, Ga 0.5 In 0.5 P-transition layer and GaAs cap layer;

[0009] Wherein, 0.6≤x1≤1, 0.4≤y1≤0.6; 0.2≤x2≤0.5, 0.4≤y2≤0.6; 0≤x3≤0.15, 0.4≤y3≤0.6; 0≤x4≤0.15, 0.4≤y4≤0.6; 0.2≤x5≤0.5, 0.4≤y5≤0.6; 0.6≤x6≤1, 0.4≤y6≤0.6; x1=x6>x5>x2.

[0010] In this invention, x1 and x6 are the same and greater than x2 and x5. The upper and lower confinement layers are each divided into two layers. The confinement layers are designed with gradients and the composition of the confinement layers varies. By confining the light field layer by layer, the light field is more concentrated in the longitudinal direction (the growth direction of the epitaxial layer), thereby improving the light confinement factor. Among them, x2 < x5, the confinement layer composition is different, and the refractive index difference between the upper confinement layer and the waveguide layer is greater. The asymmetric confinement layer design enables the light field to be shifted to the N side, reducing absorption loss and reducing threshold current.

[0011] Typically, the active region consists of upper and lower waveguide layers plus a quantum well. However, when the waveguide layer thickness is small, it cannot completely confine the light field, resulting in light leakage into the confinement layer, meaning light exists within the confinement layer. This invention adds a confinement layer with a different composition to the existing confinement layer, creating a refractive index difference within the confinement layer. This concentrates the light field within the newly added lower confinement layer 2 and upper confinement layer 1 regions, further reducing its expansion into the lower confinement layer 1 and upper confinement layer 2 regions. This concentrates the light field within the regions of lower confinement layer 2, lower waveguide layer, quantum well, upper waveguide layer, and upper confinement layer 1. This invention (A1) x2 Ga 1-x2 ) y2 In 1-y2 P-lower confinement layer two and (Al) x5 Ga 1-x5 ) y5 In 1-y5 The light field concentration region in the confinement layer on P reduces the doping concentration and decreases absorption loss.

[0012] A method for fabricating the AlGaInP red semiconductor laser device with improved light confinement factor as described above includes the following steps:

[0013] 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.

[0014] S2, the temperature is slowly reduced to 680±10℃, with a cooling rate not exceeding 30℃ / min. TMGa and AsH3 are continued to be introduced 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.

[0015] S3, the temperature is maintained at 680±10℃, growth is stopped on the GaAs buffer layer, PH3 is introduced, and growth is stopped by stopping the group V source (100% AsH3) and group III source (TMGa) for 3s to 30s, so that the As atoms in the reaction chamber are exhausted.

[0016] S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on the GaAs buffer layer. 0.5In 0.5 The purpose of the lower transition layer is to reduce band gap abrupt changes and improve electron migration rate;

[0017] S5, the temperature is maintained at 680±10℃, and TMGa, TMAl, TMIn and PH3 are introduced, in which Ga... 0.5 In 0.5 n-type (Al) grows on the lower transition layer of P. x1 Ga 1-x1 ) y1 In 1-y1 P is a restricted layer 1;

[0018] S6, the temperature is maintained at 680±10℃, and TMAl, TMGa, TMIn and PH3 are introduced, in which (Al) x1 Ga 1-x1 ) y1 In 1- y1 Growth on the lower confinement layer of P (Al) x2 Ga 1-x2 ) y2 In 1-y2 The second lower confinement layer has a different Al composition and refractive index than the first lower confinement layer, forming a gradient design to further concentrate the light field in the active region.

[0019] S7, the temperature is gradually reduced to 630±10℃, with a cooling rate not exceeding 40℃ / min, and TMAl, TMGa, TMIn, and PH3 are introduced. x2 Ga 1-x2 ) y2 In 1-y2 Growth on the second confinement layer under P (Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, where X3 < X2, and (Al) x2 Ga 1-x2 ) y2 In 1-y2 Compared to the confinement layer 2, the Al composition is reduced, so the refractive index of the waveguide layer is higher than that of the confinement layer, and the light will be confined in the waveguide layer, with the light field concentrated in the active region;

[0020] S8, the temperature is maintained at 630±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced. By adjusting the flow rates of TMIn, AsH3 and PH3, the growth of GaInAsP quantum wells with different compositions is realized, and the emission wavelength of 750-880nm is achieved.

[0021] S9, the temperature is gradually reduced to 680±10℃, and TMGa, TMIn, AsH3, and PH3 are introduced to grow (Al) on the GaInAsP quantum well. x4 Ga 1-x4 ) y4 In 1-y4 Waveguide layer on P;

[0022] S10, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x4 Ga 1-x4 ) y4 In 1- y4 (Al) grown on the waveguide layer of P x5 Ga 1-x5 ) y5 In 1-y5 P is a confined layer 1, X5 > X4, and (Al) x4 Ga 1-x4 ) y4 In 1-y4 Compared to the waveguide layer on P, the Al component increases, the optical field is concentrated in the active region, and x5 > x2, thus achieving the optical field shift towards the N side;

[0023] S11, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x5 Ga 1-x5 ) y5 In 1- y5 Growth on P-confinement layer (Al) x6 Ga 1-x6 ) y6 In 1-y6 P has a second confinement layer with a gradient design to further concentrate the light field in the active region.

[0024] S12, temperature maintained at 680±10℃, TMI, TMGa and PH3 are introduced, in the (Al) x6 Ga 1-x6 ) y6 In 1-y6 Ga is grown on the second confinement layer of P. 0.5 In 0.5 P-transition layer;

[0025] S13, reduce the temperature to 540±10℃, with a cooling rate not exceeding 40℃ / min, and continue to introduce TMGa and AsH3, while the Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P-transition layer.

[0026] 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;

[0027] Preferably, the GaAs buffer layer has a thickness of 0.2 μm and a doping concentration of 2E18 atoms / cm². 3 .

[0028] Preferably, in step S4, the Ga 0.5 In 0.5 The doping source for the transition layer under P is Si₂H₆, with a doping concentration of 2E¹⁸-5E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3 μm;

[0029] Preferred, Ga 0.5 In 0.5 The thickness of the transition layer under P is 0.2 μm, and the doping concentration is 4E18 atoms / cm. 3 .

[0030] Preferably, in step S5, the (Al) x1 Ga 1-x1 ) y1 In 1-y1 The doping source for the first confinement layer under P is Si₂H₆, with a doping concentration of 7E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 0.5-1.5μm, 0.6≤x1≤1, 0.4≤y1≤0.6;

[0031] Preferably, x1 = 1, y1 = 0.5, thickness is 1.0 μm, and doping concentration is 1E18 atoms / cm. 3 .

[0032] Preferably, in step S6, the (Al) x2 Ga 1-x2 ) y2 In 1-y2 The doping source for the second confinement layer under P is Si₂H₆, with a doping concentration of 5E¹⁷-1E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm, 0.2≤x2≤0.5, 0.4≤y2≤0.6;

[0033] Preferably, x2 = 0.2, y2 = 0.5, and the thickness is 0.2 μm. Increasing the thickness of the N-waveguide layer shifts the light field towards the N-side, and the doping concentration is 7E17 atoms / cm². 3 .

[0034] Preferably, in step S7, the (Al) x3 Ga 1-x3) y3 In 1-y3 The waveguide layer under P is unintentionally doped, with a thickness of 0.1-0.3 μm, 0≤x3≤0.15, and 0.4≤y3≤0.6;

[0035] Preferably, x3 = 0, y3 = 0.5, and the thickness is 0.2 μm.

[0036] Preferably, in step S9, the (Al) x4 Ga 1-x4 ) y4 In 1-y4 The waveguide layer on P is unintentionally doped, with a thickness of 0.1-0.3 μm, 0≤x4≤0.15, 0.4≤y4≤0.6; preferably, x4=0, y4=0.5, and a thickness of 0.1 μm;

[0037] Preferably, in step S10, the (Al) x5 Ga 1-x5 ) y5 In 1-y5 The doping source for the first confinement layer on P is Cp₂Mg, with a doping concentration of 4E¹⁷-7E¹⁷ atoms / cm². 3 The thickness is 0.1-0.3 μm, 0.2≤x5≤0.5, 0.4≤y5≤0.6; preferably, x5=0.4, y5=0.5, the thickness is 0.1 μm, and the doping concentration is 5E17 atoms / cm. 3 .

[0038] Preferably, in step S11, the (Al) x6 Ga 1-x6 ) y6 In 1-y6 The doping source for the second confinement layer on P is Cp₂Mg, with a doping concentration of 7E¹⁷-2E¹⁷ atoms / cm². 3 The thickness is 0.5-1.5 μm, 0.6 ≤ x6 ≤ 1, 0.4 ≤ y6 ≤ 0.6; preferably, x6 = 1, y6 = 0.5, the thickness is 1.0 μm, and the doping concentration is 1E18 atoms / cm. 3 .

[0039] Preferably, in step S12, the Ga 0.5 In 0.5 The doping source for the transition layer on P is Cp₂Mg, with a doping concentration of 1.2E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 20-40 nm; preferably, Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2E18 atoms / cm. 3 ;

[0040] Further, in step S13, the thickness of the GaAs 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 0.2 μm and the doping concentration is 7E19 atoms / cm². 3 .

[0041] The TMGa, TMIn, TMAl, PH3, AsH3, etc. involved in this invention are all raw materials for MOCVD epitaxial growth, and Si2H6, Cp2Mg, CBr4, DEZn, etc. are all doping sources for epitaxial growth. Except for the cap layer GaAs, the doping sources of the N and P layers are the same doping source.

[0042] Where this invention is not detailed, existing technologies may be used.

[0043] The beneficial effects of this invention are as follows:

[0044] 1) The region with the highest optical field intensity can be considered to be concentrated in the center of the total thickness of the lower waveguide layer + quantum well + upper waveguide layer. When the waveguide layer thickness is different, the optical field intensity will shift. This invention increases the thickness of the N waveguide layer (i.e., the lower waveguide layer). The region with the highest optical field intensity is in the N waveguide layer. This invention achieves the shift of the optical field to the N confinement layer through the design of the asymmetric confinement layer and waveguide layer, thereby reducing absorption loss and lowering the threshold current.

[0045] 2) This invention adds a new layer to the N and P confinement layers respectively, that is, there are two confinement layers, with x1>x2 and x6>x5. In the confinement layers, the difference in refractive index is created by using different Al compositions. A high refractive index layer is inserted into the original confinement layer to concentrate the light field, improve the light confinement factor, and reduce the threshold current.

[0046] 3) This invention reduces the doping concentration in the concentrated region of the optical field, thereby reducing absorption loss. Attached Figure Description

[0047] Figure 1 This is the conventional structure of laser devices;

[0048] Figure 2 This is a schematic diagram of the structure of the laser device of the present invention;

[0049] Figure 3 The diagram shows the refractive index and theoretical light field distribution, where (a) is the conventional structure and (b) is the structure of the present invention.

[0050] Figure 4 The diagram shows a comparison of theoretical light field distributions, where the upper dashed line represents the conventional structure and the lower dashed line represents the structure of this invention.

[0051] Figure 5 The figures show a comparison of PIV test curves, where (a) is the PIV test curve of the conventional structure and (b) is the PIV test curve of the present invention.

[0052] Among them, 1-GaAs substrate (substrate offset angle 9-15°), 2-GaAs buffer layer, 3-Ga 0.5 In 0.5 P-transition layer, 4-(Al) x1 Ga 1-x1 ) y1 In 1-y1 P-lower confinement layer one, 5-(Al) x2 Ga 1-x2 ) y2 In 1-y2 P-lower confinement layer two, 6-(Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, 7-GaInAsP quantum well, 8-(Al) x4 Ga 1-x4 ) y4 In 1-y4 P-waveguide layer, 9-(Al) x5 Ga 1-x5 ) y5 In 1-y5 P is a confined layer 1, 10-(Al) x6 Ga 1-x6 ) y6 In 1-y6 P-confinement layer two, 11-Ga 0.5 In 0.5 P-transition layer, 12-GaAs cap layer. Detailed implementation method:

[0053] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments. However, this description is not limited thereto. All aspects not described in detail in the present invention are based on conventional techniques in the field.

[0054] Example 1:

[0055] An AlGaInP red semiconductor laser device with improved light confinement factor, such as Figure 2 As shown, from bottom to top, it includes a GaAs substrate 1, a GaAs buffer layer 2, and a GaAs layer 3. 0.5 In 0.5 P-transition layer 3, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-lower confinement layer 14, (Al) x2 Ga1-x2 ) y2 In 1-y2 P Lower confinement layer 2 5, (Al) x3 Ga 1-x3 ) y3 In 1-y3 6. Lower waveguide layer of P, 7. GaInAsP quantum well, (Al) x4 Ga 1-x4 ) y4 In 1-y4 P upper waveguide layer 8, (Al) x5 Ga 1-x5 ) y5 In 1-y5 P upper confinement layer 19, (Al) x6 Ga 1-x6 ) y6 In 1-y6 P upper confinement layer 2 10, Ga 0.5 In 0.5 P-transition layer 11 and GaAs cap layer 12;

[0056] Wherein, 0.6≤x1≤1, 0.4≤y1≤0.6; 0.2≤x2≤0.5, 0.4≤y2≤0.6; 0≤x3≤0.15, 0.4≤y3≤0.6; 0≤x4≤0.15, 0.4≤y4≤0.6; 0.2≤x5≤0.5, 0.4≤y5≤0.6; 0.6≤x6≤1, 0.4≤y6≤0.6; x1=x6>x5>x2.

[0057] In this invention, x1 and x6 are the same and greater than x2 and x5. The upper and lower confinement layers are each divided into two layers. The confinement layers are designed with gradients and the composition of the confinement layers varies. By confining the light field layer by layer, the light field is more concentrated in the longitudinal direction (the growth direction of the epitaxial layer), thereby improving the light confinement factor. Among them, x2 < x5, the confinement layer composition is different, and the refractive index difference between the upper confinement layer and the waveguide layer is greater. The asymmetric confinement layer design enables the light field to be shifted to the N side, reducing absorption loss and reducing threshold current.

[0058] like Figure 1 As shown, this is a conventional structure, typically with upper and lower waveguide layers plus a quantum well as the active region. However, when the waveguide layer thickness is small (generally less than 1 μm), it cannot completely confine the light field, resulting in light leakage into the confinement layer, meaning light exists within the confinement layer. This invention adds a confinement layer with a different composition within the confinement layer, creating a refractive index difference within the confinement layer. This concentrates the light field in the newly added lower confinement layer 2 and upper confinement layer 1 regions, further reducing its expansion into the lower confinement layer 1 and upper confinement layer 2 regions. This concentrates the light field in the regions of lower confinement layer 2, lower waveguide layer, quantum well, upper waveguide layer, and upper confinement layer 1. This invention (Al) x2 Ga 1-x2 )y2 In 1-y2 P-lower confinement layer two and (Al) x5 Ga 1-x5 ) y5 In 1-y5 The light field concentration region in the confinement layer on P reduces the doping concentration and decreases absorption loss.

[0059] Example 2:

[0060] A method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor includes the following steps:

[0061] 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.

[0062] S2, the temperature is slowly reduced to 680±10℃, with a cooling rate not exceeding 30℃ / min. TMGa and AsH3 are continued to be introduced 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.

[0063] 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 ;

[0064] S3, the temperature is maintained at 680±10℃, growth is stopped on the GaAs buffer layer, PH3 is introduced, and growth is stopped by stopping the group V source (100% AsH3) and group III source (TMGa) for 3s to 30s, so that the As atoms in the reaction chamber are exhausted.

[0065] S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on the GaAs buffer layer. 0.5 In 0.5 The purpose of the lower transition layer is to reduce the band gap abrupt change and improve the electron migration rate;

[0066] Ga 0.5 In 0.5 The doping source for the transition layer under P is Si₂H₆, and the doping concentration is 4E¹⁸ atoms / cm². 3 Ga 0.5 In 0.5 The thickness of the transition layer under P is 0.2 μm;

[0067] S5, the temperature is maintained at 680±10℃, and TMGa, TMAl, TMIn and PH3 are introduced, in which Ga... 0.5 In0.5 n-type (Al) grows on the lower transition layer of P. x1 Ga 1-x1 ) y1 In 1-y1 P is a restricted layer 1;

[0068] (Al x1 Ga 1-x1 ) y1 In 1-y1 The doping source for the first confinement layer under P is Si₂H₆, x₁ = 1, y₁ = 0.5, with a thickness of 1.0 μm and a doping concentration of 1E¹⁸ atoms / cm². 3 ;

[0069] S6, the temperature is maintained at 680±10℃, and TMAl, TMGa, TMIn and PH3 are introduced, in which (Al) x1 Ga 1-x1 ) y1 In 1- y1 Growth on the lower confinement layer of P (Al) x2 Ga 1-x2 ) y2 In 1-y2 The second lower confinement layer has a different Al composition and refractive index than the first lower confinement layer, forming a gradient design to further concentrate the light field in the active region.

[0070] (Al x2 Ga 1-x2 ) y2 In 1-y2 The doping source for the second confinement layer under P is Si₂H₆, with a doping concentration of 5E¹⁷-1E¹⁸ atoms / cm². 3 With x² = 0.2, y² = 0.5, and a thickness of 0.2 μm, the thickness of the N-waveguide layer is increased to shift the light field towards the N-side. The doping concentration is 7E¹⁷ atoms / cm². 3 ;

[0071] S7, the temperature is gradually reduced to 630±10℃, with a cooling rate not exceeding 40℃ / min, and TMAl, TMGa, TMIn, and PH3 are introduced. x2 Ga 1-x2 ) y2 In 1-y2 Growth on the second confinement layer under P (Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, where X3 < X2, and (Al) x2 Ga 1-x2 ) y2 In 1-y2Compared to the confinement layer 2, the Al composition is reduced, so the refractive index of the waveguide layer is higher than that of the confinement layer, and the light will be confined in the waveguide layer, with the light field concentrated in the active region;

[0072] (Al x3 Ga 1-x3 ) y3 In 1-y3 The waveguide layer under P is unintentionally doped, x3 = 0, y3 = 0.5, and has a thickness of 0.2 μm;

[0073] S8, the temperature is maintained at 630±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced. By adjusting the flow rates of TMIn, AsH3 and PH3, the growth of GaInAsP quantum wells with different compositions is realized, and the emission wavelength of 750-880nm is achieved.

[0074] S9, the temperature is gradually reduced to 680±10℃, and TMGa, TMIn, AsH3, and PH3 are introduced to grow (Al) on the GaInAsP quantum well. x4 Ga 1-x4 ) y4 In 1-y4 Waveguide layer on P;

[0075] (Al x4 Ga 1-x4 ) y4 In 1-y4 The waveguide layer on P is unintentionally doped, with x4 = 0, y4 = 0.5, and a thickness of 0.1 μm;

[0076] S10, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x4 Ga 1-x4 ) y4 In 1- y4 (Al) grown on the waveguide layer of P x5 Ga 1-x5 ) y5 In 1-y5 P is a confined layer 1, X5 > X4, and (Al) x4 Ga 1-x4 ) y4 In 1-y4 Compared to the waveguide layer on P, the Al component increases, the optical field is concentrated in the active region, and x5 > x2, thus achieving the optical field shift towards the N side;

[0077] (Al x5 Ga 1-x5 ) y5 In 1-y5The doping source for the first confinement layer on P is Cp₂Mg, x₅ = 0.4, y₅ = 0.5, with a thickness of 0.1 μm and a doping concentration of 5E¹⁷ atoms / cm². 3 ;

[0078] S11, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x5 Ga 1-x5 ) y5 In 1- y5 Growth on P-confinement layer (Al) x6 Ga 1-x6 ) y6 In 1-y6 P has a second confinement layer with a gradient design to further concentrate the light field in the active region.

[0079] (Al x6 Ga 1-x6 ) y6 In 1-y6 The doping source for the second confinement layer on P is Cp₂Mg, x₆ = 1, y₆ = 0.5, with a thickness of 1.0 μm and a doping concentration of 1E¹⁸ atoms / cm². 3 ;

[0080] S12, temperature maintained at 680±10℃, TMI, TMGa and PH3 are introduced, in the (Al) x6 Ga 1-x6 ) y6 In 1-y6 Ga is grown on the second confinement layer of P. 0.5 In 0.5 P-transition layer;

[0081] Ga 0.5 In 0.5 The doping source for the transition layer on P is Cp₂Mg, Ga 0.5 In 0.5 The thickness of the transition layer on P is 24 nm, and the doping concentration is 2E18 atoms / cm. 3 ;

[0082] S13, reduce the temperature to 540±10℃, with a cooling rate not exceeding 40℃ / min, and continue to introduce TMGa and AsH3, while the Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P-transition layer;

[0083] The GaAs cap layer has a thickness of 0.1-0.5 μm, the doping source is CBr4, the thickness is 0.2 μm, and the doping concentration is 7E19 atoms / cm³. 3 .

[0084] Because the refractive index difference between the waveguide layer and the confinement layer cannot completely confine the light field, there is a phenomenon where the light field extends into the confinement layer to a certain extent, such as... Figure 1 , 2 As can be seen from the comparative structure, the present invention adds a second lower confinement layer and a first upper confinement layer, and designs a gradient confinement layer with a refractive index difference in the original confinement layer, which reduces the extension of the light field to the far end of the confinement layer, makes the light field more concentrated near the active region, improves the light confinement factor, and reduces the threshold current.

[0085] like Figure 3 As shown in (a) and (b), the upper and lower confining layers of this invention are each two layers, and through changes in the component gradient, as... Figure 3 (b) The increased gradient reduces the extension of the light field to the far end of the confinement layer, such as Figure 4 d1 represents the optical field loss in the conventional structure, and d2 represents the optical field loss in the structure of this invention. This makes the optical field more concentrated near the active region, increases the optical power density, and helps to improve the optical confinement factor. Reducing the doping concentration in the concentrated optical field region helps to reduce absorption loss and lower the threshold current.

[0086] Figure 5 The PIV test curves of the conventional structure and the laser device described in this invention are compared under a cavity length of 450 μm and a stripe width of 5 μm. The horizontal axis represents the operating current, the left vertical axis represents the output power, and the right vertical axis represents the operating voltage. The comparison results show that the threshold currents of the conventional structure and the laser device described in this invention are 17.2 mA and 6.9 mA, respectively. It can be seen that the present invention, through gradient confinement layer design and asymmetric structure design, concentrates the light field, improves the light confinement factor, reduces doping in the concentrated light field region, reduces absorption loss, and improves photoelectric conversion efficiency.

[0087] 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. An AlGaInP red semiconductor laser device with improved optical confinement factor, characterized in that, From bottom to top, it includes a GaAs substrate, a GaAs buffer layer, and a GaAs layer. 0.5 In 0.5 P-transition layer, (Al) x1 Ga 1-x1 ) y1 In 1-y1 P-lower confinement layer 1, (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-lower confinement layer two, (Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, GaInAsP quantum well, (Al) x4 Ga 1-x4 ) y4 In 1-y4 P upper waveguide layer, (Al) x5 Ga 1-x5 ) y5 In 1-y5 P upper confinement layer one, (Al) x6 Ga 1-x6 ) y6 In 1-y6 P upper confinement layer 2, Ga 0.5 In 0.5 P-transition layer and GaAs cap layer; Wherein, 0.6≤x1≤1, 0.4≤y1≤0.6; 0.2≤x2≤0.5, 0.4≤y2≤0.6; 0≤x3≤0.15, 0.4≤y3≤0.6; 0≤x4≤0.15, 0.4≤y4≤0.6; 0.2≤x5≤0.5, 0.4≤y5≤0.6; 0.6≤x6≤1, 0.4≤y6≤0.6; x1=x6>x5>x2.

2. A method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor 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, the temperature is slowly reduced to 680±10℃, with a cooling rate not exceeding 30℃ / min, and TMGa and AsH3 are continued to be introduced 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, growth is stopped by stopping the group V source and group III source, the stop is 3s to 30s, and the As atoms in the reaction chamber are exhausted. S4, with the temperature maintained at 680±10℃, TMGa, TMIn, and PH3 are introduced to grow Ga on the GaAs buffer layer. 0.5 In 0.5 P-level transition layer; S5, the temperature is maintained at 680±10℃, and TMGa, TMAl, TMIn and PH3 are introduced, in which Ga... 0.5 In 0.5 n-type (Al) grows on the lower transition layer of P. x1 Ga 1-x1 ) y1 In 1-y1 P is a restricted layer 1; S6, the temperature is maintained at 680±10℃, and TMAl, TMGa, TMIn and PH3 are introduced, in which (Al) x1 Ga 1-x1 ) y1 In 1-y1 Growth on the lower confinement layer of P (Al) x2 Ga 1-x2 ) y2 In 1-y2 P-level confinement layer two; S7, the temperature is gradually reduced to 630±10℃, with a cooling rate not exceeding 40℃ / min, and TMAl, TMGa, TMIn, and PH3 are introduced. x2 Ga 1-x2 ) y2 In 1-y2 Growth on the second confinement layer under P (Al) x3 Ga 1-x3 ) y3 In 1-y3 P-waveguide layer, where X3 < X2, and (Al) x2 Ga 1-x2 ) y2 In 1-y2 Compared to the second confinement layer under P, the Al composition is reduced; S8, the temperature is maintained at 630±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced to grow GaInAsP quantum wells; S9, the temperature is gradually reduced to 680±10℃, and TMGa, TMIn, AsH3, and PH3 are introduced to grow (Al) on the GaInAsP quantum well. x4 Ga 1-x4 ) y4 In 1-y4 Waveguide layer on P; S10, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x4 Ga 1-x4 ) y4 In 1-y4 Growth on waveguide layer P (Al) x5 Ga 1-x5 ) y5 In 1-y5 P is a confined layer 1, X5 > X4, and (Al) x4 Ga 1-x4 ) y4 In 1-y4 Compared to the waveguide layer on P, the Al component is increased; S11, the temperature is maintained at 680±10℃, and TMGa, TMIn, AsH3 and PH3 are introduced, in the (Al) x5 Ga 1-x5 ) y5 In 1-y5 Growth on P-limiting layer (Al) x6 Ga 1-x6 ) y6 In 1-y6 P is restricted by layer two; S12, temperature maintained at 680±10℃, TMI, TMGa and PH3 are introduced, in the (Al) x6 Ga 1-x6 ) y6 In 1-y6 Ga is grown on the second confinement layer of P. 0.5 In 0.5 P-transition layer; S13, reduce the temperature to 540±10℃, with a cooling rate not exceeding 40℃ / min, and continue to introduce TMGa and AsH3, while the Ga... 0.5 In 0.5 A GaAs cap layer is grown on the P-transition layer.

3. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, 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 0.1-0.3μm.

4. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S4, the Ga 0.5 In 0.5 The doping source for the transition layer under P is Si₂H₆, with a doping concentration of 2E¹⁸-5E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm.

5. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S5, the (Al) x1 Ga 1-x1 ) y1 In 1-y1 The doping source for the first confinement layer under P is Si₂H₆, with a doping concentration of 7E¹⁷-2E¹⁸ atoms / cm². 3 The thickness is 0.5-1.5μm, 0.6≤x1≤1, 0.4≤y1≤0.

6.

6. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S6, the (Al) x2 Ga 1-x2 ) y2 In 1-y2 The doping source for the second confinement layer under P is Si₂H₆, with a doping concentration of 5E¹⁷-1E¹⁸ atoms / cm². 3 The thickness is 0.1-0.3μm, 0.2≤x2≤0.5, 0.4≤y2≤0.

6.

7. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S7, the (Al) x3 Ga 1-x3 ) y3 In 1-y3 The waveguide layer under P is unintentionally doped, with a thickness of 0.1-0.3 μm, 0≤x3≤0.15, and 0.4≤y3≤0.

6.

8. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S9, the (Al) x4 Ga 1-x4 ) y4 In 1-y4 The waveguide layer on P is unintentionally doped, with a thickness of 0.1-0.3 μm, 0≤x4≤0.15, and 0.4≤y4≤0.6; In step S10, the (A1) x5 Ga 1-x5 ) y5 In 1-y5 The doping source for the first confinement layer on P is Cp₂Mg, with a doping concentration of 4E¹⁷-7E¹⁷ atoms / cm². 3 The thickness is 0.1-0.3μm, 0.2≤x5≤0.5, 0.4≤y5≤0.

6.

9. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S11, the (A1) x6 Ga 1-x6 ) y6 In 1-y6 The doping source for the second confinement layer on P is Cp₂Mg, with a doping concentration of 7E¹⁷-2E¹⁷ atoms / cm². 3 The thickness is 0.5-1.5μm, 0.6≤x6≤1, 0.4≤y6≤0.

6.

10. The method for fabricating an AlGaInP red semiconductor laser device with improved optical confinement factor according to claim 2, characterized in that, In step S12, the Ga 0.5 In 0.5 The doping source for the transition layer on P is Cp₂Mg, with a doping concentration of 1.2E¹⁸-3E¹⁸ atoms / cm². 3 The thickness is 20-40nm; In step S13, the thickness of the GaAs 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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