Gallium nitride-based semiconductor laser with stray diffraction light spot suppression layer

Abstract

The invention provides a gallium nitride-based semiconductor laser with a stray diffraction light spot suppression layer. The gallium nitride-based semiconductor laser comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper limiting layer which are sequentially arranged from bottom to top. An SIMS test Al atom concentration or Al ion strength curve of the lower limiting layer, a refractive index distribution curve of the lower limiting layer, an SIMS test Al atom concentration or Al ion strength curve of the upper limiting layer, an EDX test Al relative atom strength curve of the upper limiting layer and a refractive index distribution curve of the upper limiting layer all have Boltzmann function distribution; therefore, steep refractive index turning is formed on the interface of the first stray diffraction light spot suppression lower limiting layer and the second stray diffraction light spot suppression lower limiting layer and the interface of the first stray diffraction light spot suppression upper limiting layer and the second stray diffraction light spot suppression upper limiting layer. The laser is regulated and controlled to penetrate through the interface of the upper limiting layer and the lower limiting layer to be focused or diverged, so that a light spot is split into a compact bright spot from a diffraction diffusion light spot.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor optoelectronic devices, in particular to a gallium nitride-based semiconductor laser with a stray diffraction spot layer. BACKGROUND

[0002] Lasers are widely used in laser display, laser television, laser projector, communication, medical treatment, weapon, guidance, ranging, spectrum analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and the classification methods are various. The main types of lasers include solid-state, gas, liquid, semiconductor and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers have the advantages of small size, high efficiency, light weight, good stability, long service life, simple and compact structure, and small size.

[0003] There are great differences between lasers and nitride semiconductor light-emitting diodes: 1) Laser is generated by stimulated radiation of carriers, with small spectral half-width and high brightness. The output power of a single laser can reach W level, while the output power of a single nitride semiconductor light-emitting diode is in mW level; 2) The current density of the laser reaches KA / cm2, which is more than 2 orders of magnitude higher than that of the nitride light-emitting diode, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect, more serious electron-hole mismatch, and more serious efficiency droop effect; 3) Light-emitting diode is self-transition radiation without external action, and the incoherent light jumps from high energy level to low energy level, while laser is stimulated transition radiation, and the energy of the induced photon should be equal to the energy level difference of the electron transition, producing homophase coherent light of photons and induced photons; 4) Different principles: light-emitting diode is the transition of electron-hole to active layer or p-n junction under the action of external voltage to produce radiation recombination and light emission, while laser needs to meet the lasing conditions, and must meet the carrier inversion distribution in the active region. The stimulated radiation light oscillates back and forth in the resonant cavity, propagates in the gain medium to amplify the light, and finally outputs the laser when the gain is greater than the loss and the threshold condition is met.

[0004] The nitride semiconductor laser has the following problems: GaN-based laser often has spot diffraction diffusion and spot splitting in the far-field image, resulting in stray light and speckle problems during use. SUMMARY

[0005] To solve one of the above technical problems, the present application provides a gallium nitride-based semiconductor laser with a stray diffraction spot layer.

[0006] The embodiment of the present application provides a gallium nitride-based semiconductor laser with a stray diffraction light spot layer, which comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper limiting layer arranged from bottom to top, the lower limiting layer comprises a first stray diffraction light spot lower limiting layer and a second stray diffraction light spot lower limiting layer, the first stray diffraction light spot lower limiting layer is located below the second stray diffraction light spot lower limiting layer, the upper limiting layer comprises a first stray diffraction light spot upper limiting layer and a second stray diffraction light spot upper limiting layer, the first stray diffraction light spot upper limiting layer is located below the second stray diffraction light spot upper limiting layer. The SIMS test Al atomic concentration or Al ion intensity curve of the lower limiting layer, the refractive index distribution curve of the lower limiting layer, the SIMS test Al atomic concentration or Al ion intensity curve of the upper limiting layer, the EDX test Al relative atomic intensity curve of the upper limiting layer and the refractive index distribution curve of the upper limiting layer all have a Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution, wherein y is the SIMS test Al atomic concentration or Al ion intensity, x is the SIMS test epitaxial layer thickness, the starting point 0 is the surface of the epitaxial layer, A1 is the initial asymptotic value, A2 is the final asymptotic value, x0 is the midpoint and dx is the change rate parameter.

[0007] Preferably, in the SIMS test Al atomic concentration or Al ion intensity curve function of the lower limiting layer, 5E18<=A1<=5E21, 5E17<=A2<=5E20, 1<=x0<=6 and 0.0002<=dx<=0.2.

[0008] Preferably, in the SIMS test Al atomic concentration or Al ion intensity curve function of the upper limiting layer, 5E14<=A1<=5E18, 5E18<=A2<=5E21, 0.03<=x0<=3 and 0.0001<=dx<=0.1.

[0009] Preferably, in the SIMS test Al atomic concentration or Al ion intensity curve function of the lower limiting layer and the SIMS test Al atomic concentration or Al ion intensity curve function of the upper limiting layer, the initial asymptotic value of the lower limiting layer is greater than or equal to the initial asymptotic value of the upper limiting layer, the final asymptotic value of the lower limiting layer is less than or equal to the final asymptotic value of the upper limiting layer, the midpoint of the lower limiting layer is greater than or equal to the midpoint of the upper limiting layer, the change rate parameter of the lower limiting layer is greater than or equal to the change rate parameter of the upper limiting layer, 100<=A1 of the lower limiting layer / A1 of the upper limiting layer<=5000, 0.05<=A2 of the lower limiting layer / A2 of the upper limiting layer<=5, 1<=x0 of the lower limiting layer / x0 of the upper limiting layer<=20 and 0.2<=dx of the lower limiting layer / dx of the upper limiting layer<=20.

[0010] Preferably, the SIMS tested Al atomic concentration or Al ion intensity of the first stray diffraction light spot under limiting layer is greater than or equal to the SIMS tested Al atomic concentration or Al ion intensity of the second stray diffraction light spot under limiting layer.

[0011] Preferably, in the Al relative atomic intensity curve function of the EDX test of the upper limiting layer: 0.05≤A1≤5, 0.5≤A2≤50, 50≤x0≤5000, 0.5≤dx≤50.

[0012] Preferably, in the refractive index distribution curve function of the lower limiting layer: 1≤A1≤5, 1≤A2≤5, 1≤x0≤5, 0.0001≤dx≤0.1; in the refractive index distribution curve function of the upper limiting layer: 1≤A1≤5, 1≤A2≤5, 0.1≤x0≤1, 0.0001≤dx≤0.1; A turning angle of 75°≤α≤90° is formed between the first stray diffraction light spot under limiting layer and the second stray diffraction light spot under limiting layer. A turning angle of 75°≤β≤90° is formed between the first stray diffraction light spot under limiting layer and the second stray diffraction light spot under limiting layer.

[0013] Preferably, the piezoelectric polarization coefficient distribution curve of the lower limiting layer and the piezoelectric polarization coefficient distribution curve of the upper limiting layer both have a Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution; In the piezoelectric polarization coefficient distribution curve function of the lower limiting layer: 0.05≤A1≤5, 0.01≤A2≤5, 0.5≤x0≤10, 0.0002≤dx≤0.2; In the piezoelectric polarization coefficient distribution curve function of the upper limiting layer: 0.05≤A1≤5, 0.05≤A2≤5, 0.01≤x0≤5, 0.0001≤dx≤0.1; A turning angle of 75°≤γ≤90° is formed between the first stray diffraction light spot under limiting layer and the second stray diffraction light spot under limiting layer. A turning angle of 75°≤θ≤90° is formed between the first stray diffraction light spot under limiting layer and the second stray diffraction light spot under limiting layer.

[0014] Preferably, the first confinement layer under the stray diffraction suppression spot is any combination of GaN, AlGaN, and AlN, and the thickness of the first confinement layer under the stray diffraction suppression spot is 50 nm to 5000 nm. The second confinement layer under the stray diffraction suppression spot is any combination of GaN, AlGaN, and AlN, and the thickness of the second confinement layer under the stray diffraction suppression spot is 50 nm to 8000 nm. The confinement layer on the first stray diffraction suppression spot is any combination of AlGaN, GaN, and AlN; The confinement layer on the second stray diffraction suppression spot is any combination of AlGaN, GaN, and AlN.

[0015] Preferably, the substrate is a GaN single crystal substrate; The lower waveguide layer is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the lower waveguide layer is from 300 angstroms to 8000 angstroms. The active layer is an InGaN / GaN quantum well; The upper waveguide layer is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the upper waveguide layer is from 300 angstroms to 8000 angstroms. The electron blocking layer is any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, and the thickness of the electron blocking layer is from 5 angstroms to 800 angstroms.

[0016] The beneficial effects of this invention are as follows: This invention ensures that the SIMS test curves of Al atom concentration or Al ion intensity in the lower confinement layer, the refractive index distribution curve of the lower confinement layer, the SIMS test curves of Al atom concentration or Al ion intensity in the upper confinement layer, the EDX test curves of Al relative atomic intensity in the upper confinement layer, and the refractive index distribution curve of the upper confinement layer in the gallium nitride-based semiconductor laser all have Boltzmann function distributions. As a result, a steep refractive index transition is formed at the interface between the lower confinement layer and the second lower confinement layer of the first stray diffraction spot, as well as at the interface between the upper confinement layer and the second upper confinement layer of the first stray diffraction spot. This controls the focusing or divergence of the laser as it passes through the interface between the upper and lower confinement layers, causing the light spot to split from a diffracted diffused pattern into a compact bright spot. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to an embodiment of the present invention; Figure 2 This is a SIMS secondary ion mass spectrum and a schematic diagram of the x and y coordinates of a gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in an embodiment of the present invention. Figure 3 The following is a SIMS secondary ion mass spectrum and fitting curve of the lower confinement layer of the gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in the embodiments of the present invention; Figure 4 This is a TEM transmission electron microscope image of the lower confinement layer of a gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in an embodiment of the present invention. Figure 5 The above-described SIMS secondary ion mass spectrum and fitting curve of the gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to an embodiment of the present invention are shown. Figure 6 The images and fitting curves show the EDX (Energy Dispersive X-ray Spectroscopy) test results of the upper confinement layer of the gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in the embodiments of the present invention. Figure 7 This is a TEM transmission electron microscope image of the upper confinement layer of a gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in an embodiment of the present invention. Figure 8 This is a comparison of far-field images of a conventional laser and a gallium nitride-based semiconductor laser with a stray diffraction suppression layer as described in the embodiments of the present invention. Figure 9 The diagram shows the refractive index distribution and refractive index fitting curve of the lower confinement layer of the gallium nitride-based semiconductor laser with a divergence angle control layer according to an embodiment of the present invention. Figure 10 The diagram shows the refractive index distribution and refractive index fitting curve of the upper confinement layer of the gallium nitride-based semiconductor laser with a divergence angle control layer according to an embodiment of the present invention. Figure 11 The diagram shows the piezoelectric polarization coefficient distribution and fitting curve of the lower confinement layer of the gallium nitride-based semiconductor laser with a divergence angle control layer according to an embodiment of the present invention. Figure 12The diagram shows the piezoelectric polarization coefficient distribution and fitting curve of the upper confinement layer of the gallium nitride-based semiconductor laser with a divergence angle control layer according to an embodiment of the present invention.

[0018] Figure label: 100. Substrate; 101. Lower confinement layer; 102. Lower waveguide layer; 103. Active layer; 104. Upper waveguide layer; 105. Electron blocking layer; 106. Upper confinement layer. 101a, First stray diffraction suppression lower confinement layer; 101b, Second stray diffraction suppression lower confinement layer; 106a, First confinement layer for suppressing stray diffraction spots; 106b, Second confinement layer for suppressing stray diffraction spots. Detailed Implementation

[0019] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] like Figures 1 to 12 As shown, this embodiment proposes a gallium nitride-based semiconductor laser with a stray diffraction suppression layer, comprising, from bottom to top, a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105, and an upper confinement layer 106. In this embodiment, the lower confinement layer 101 and the upper confinement layer 106 are respectively the lower confinement layer and the upper confinement layer for suppressing stray diffraction spots.

[0021] Specifically, such as Figure 1As shown, in this embodiment, the gallium nitride-based semiconductor laser is provided with, from bottom to top, a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105, and an upper confinement layer 106. The lower confinement layer 101 and the upper confinement layer 106 are respectively a lower confinement layer for suppressing stray diffraction spots and an upper confinement layer for suppressing stray diffraction spots. Both the lower confinement layer 101 and the upper confinement layer 106 are double-layer structures. The lower confinement layer 101 includes a first lower confinement layer for suppressing stray diffraction spots 101a and a second lower confinement layer for suppressing stray diffraction spots 101b, with the first lower confinement layer for suppressing stray diffraction spots 101a located below the second lower confinement layer for suppressing stray diffraction spots 101b. The upper confinement layer 106 includes a first stray diffraction suppression spot upper confinement layer 106a and a second stray diffraction suppression spot upper confinement layer 106b, with the first stray diffraction suppression spot upper confinement layer 106a located below the second stray diffraction suppression spot upper confinement layer 106b.

[0022] In this embodiment, the lower confinement layer 101 has Al atom concentration or Al ion intensity distribution characteristics and refractive index distribution characteristics, while the upper confinement layer 106 has Al atom concentration or Al ion intensity distribution characteristics, Al relative atomic intensity distribution characteristics, and refractive index distribution characteristics. Furthermore, the SIMS test curves of Al atom concentration or Al ion intensity in the lower confinement layer 101, the refractive index distribution curves of the lower confinement layer 101, the SIMS test curves of Al atom concentration or Al ion intensity in the upper confinement layer 106, the EDX test curves of Al relative atomic intensity in the upper confinement layer 106, and the refractive index distribution curves of the upper confinement layer 106 all exhibit a Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution, as shown below. Figures 2 to 10 As shown in the figure. Where: y is the dependent variable, which is the Al atom concentration or Al ion intensity measured by SIMS; x is the independent variable, specifically the epitaxial layer thickness measured by SIMS; the starting point 0 is the epitaxial layer surface; A1 is the initial asymptotic value, which is the limit value that y approaches when x approaches negative infinity (the "plateau" value on the left side of the curve); A2 is the final asymptotic value, which is the limit value that y approaches when x approaches positive infinity (the "plateau" value on the right side of the curve); x0 is the midpoint, i.e., the inflection point, the x value corresponding to the steepest change in the curve, which is exactly in the middle of the two asymptotic values; dx is the rate of change parameter, which controls the steepness of the "transition zone" of the curve.

[0023] Specifically, such as Figure 3 and Figure 4As shown, in the SIMS test Al atom concentration or Al ion intensity curve function of the lower confinement layer 101: 5E18≤A1≤5E21, 5E17≤A2≤5E20, 1≤x0≤6, 0.0002≤dx≤0.2. Within the range of these function parameters, the SIMS test Al atom concentration or Al ion intensity curve of the lower confinement layer 101 in this embodiment can have the following Boltzmann function curve distribution: y=5.02174E19+(1.3533E20-5.02174E19) / (1+exp((x-2.80798) / 0.00298)) like Figure 5 and Figure 7 As shown, in the SIMS test Al atom concentration or Al ion intensity curve function of the upper confinement layer 106: 5E14≤A1≤5E18, 5E18≤A2≤5E21, 0.03≤x0≤3, 0.0001≤dx≤0.1. Within the range of these function parameters, the SIMS test Al atom concentration or Al ion intensity curve of the upper confinement layer 106 in this embodiment can have the following Boltzmann function curve distribution: y=1.10472E20+(8.01882E16-1.10472E20) / (1+exp((x-0.36137) / 0.00156)) More specifically, in the SIMS test Al atom concentration or Al ion intensity curve function of the lower confinement layer 101 and the SIMS test Al atom concentration or Al ion intensity curve function of the upper confinement layer 106, the initial asymptotic value of the lower confinement layer 101 is greater than or equal to the initial asymptotic value of the upper confinement layer 106, the final asymptotic value of the lower confinement layer 101 is less than or equal to the final asymptotic value of the upper confinement layer 106, the midpoint of the lower confinement layer 101 is greater than or equal to the midpoint of the upper confinement layer 106, the rate of change parameter of the lower confinement layer 101 is greater than or equal to the rate of change parameter of the upper confinement layer 106, and 100≤lower confinement layer A1 / upper confinement layer A1≤5000, 0.05≤lower confinement layer A2 / upper confinement layer A2≤5, 1≤lower confinement layer x0 / upper confinement layer x0≤20, and 0.2≤lower confinement layer dx / upper confinement layer dx≤20.

[0024] Taking the SIMS test Al atom concentration or Al ion intensity curve distribution function of the lower confinement layer 101 and the SIMS test Al atom concentration or Al ion intensity curve distribution function of the upper confinement layer 106 as examples above, the ratio of lower confinement layer A1 to upper confinement layer A1 is 1688, the ratio of lower confinement layer A2 to upper confinement layer A2 is 0.45, the ratio of lower confinement layer x0 to upper confinement layer x0 is 7.77, and the ratio of lower confinement layer dx to upper confinement layer dx is 1.91.

[0025] In some alternative embodiments, the SIMS test Al atom concentration or Al ion intensity of the confinement layer 101a under the first stray diffraction suppression spot is greater than or equal to the SIMS test Al atom concentration or Al ion intensity of the confinement layer 101b under the second stray diffraction suppression spot.

[0026] like Figure 6 As shown, in this embodiment, the Al relative atomic intensity curve function of the EDX test of the upper confinement layer 106 has the following parameters: 0.05≤A1≤5, 0.5≤A2≤50, 50≤x0≤5000, 0.5≤dx≤50. Within this parameter range, the Al relative atomic intensity curve of the EDX test of the upper confinement layer 106 in this embodiment can have the following Boltzmann function curve distribution: y=3.1342+(0.84551-3.1342) / (1+exp((x-344.11294) / 1.78049)) like Figure 9 As shown, in this embodiment, the refractive index distribution curve function of the lower confinement layer 101 has the following parameters: 1≤A1≤5, 1≤A2≤5, 1≤x0≤5, 0.0001≤dx≤0.1. Within the range of these parameters, the refractive index distribution curve of the lower confinement layer 101 in this embodiment can have the following Boltzmann function curve distribution: y=2.28913+(2.27071-2.28913) / (1+exp((x-2.80798) / 0.00298)) like Figure 10 As shown, in this embodiment, the refractive index distribution curve function of the upper confinement layer 106 has the following parameters: 1≤A1≤5, 1≤A2≤5, 0.1≤x0≤1, 0.0001≤dx≤0.1. Within the range of these parameters, the refractive index distribution curve of the upper confinement layer 106 in this embodiment can have the following Boltzmann function curve distribution: y=2.27063+(2.29998-2.27063) / (1+exp((x-0.36137) / 0.00156)) In addition, such as Figure 9 As shown, a refractive index transition region of the lower confinement layer 101 is formed between the first lower confinement layer 101a and the second lower confinement layer 101b that suppresses stray diffraction spots, and the transition angle of this refractive index transition region of the lower confinement layer 101 is 75°≤α≤90°. Figure 10As shown, a refractive index transition region of the upper confinement layer 106 is formed between the first stray diffraction suppression spot upper confinement layer 106a and the second stray diffraction suppression spot upper confinement layer 106b, and the transition angle of the refractive index transition region of the upper confinement layer 106 is 75°≤β≤90°, and 75°≤β≤α≤90°.

[0027] In this embodiment, the SIMS test curves of Al atom concentration or Al ion intensity of the lower confinement layer 101, the refractive index distribution curve of the lower confinement layer 101, the SIMS test curves of Al atom concentration or Al ion intensity of the upper confinement layer 106, the EDX test curves of Al relative atomic intensity of the upper confinement layer 106, and the refractive index distribution curve of the upper confinement layer 106 all exhibit Boltzmann function distributions. This results in a steep refractive index transition at the interface between the lower confinement layer 101a and the lower confinement layer 101b of the first stray diffraction spot, and at the interface between the upper confinement layer 106a and the upper confinement layer 106b of the first stray diffraction spot. This controls the focusing or divergence of the laser as it passes through the interface between the upper confinement layer 106 and the lower confinement layer 101, causing the light spot to split from a diffracted, diffused pattern into a compact, bright spot. Figure 8 As shown, where, Figure 8 a represents a stray diffraction spot. Figure 8 b represents a stray diffraction-free spot.

[0028] In some alternative embodiments, such as Figure 11 and Figure 12 As shown, the piezoelectric polarization coefficient distribution curves of the lower confinement layer 101 and the upper confinement layer 106 both have the Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution.

[0029] Specifically, such as Figure 11 As shown, in the piezoelectric polarization coefficient distribution curve function of the lower confinement layer 101: 0.05≤A1≤5, 0.01≤A2≤5, 0.5≤x0≤10, 0.0002≤dx≤0.2; within the range of these function parameters, the piezoelectric polarization coefficient distribution curve of the lower confinement layer 101 in this embodiment can have the following Boltzmann function curve distribution: y=0.7829+(0.87255-0.7829) / (1+exp((x-2.80798) / 0.00298)) like Figure 12As shown, in the piezoelectric polarization coefficient distribution curve function of the upper confinement layer 106: 0.05≤A1≤5, 0.05≤A2≤5, 0.01≤x0≤5, 0.0001≤dx≤0.1; within the range of these function parameters, the piezoelectric polarization coefficient distribution curve of the upper confinement layer 106 in this embodiment can have the following Boltzmann function curve distribution: y=0.87294+(0.7301-0.87294) / (1+exp((x-0.36137) / 0.00156)) More specifically, such as Figure 11 As shown, a piezoelectric polarization coefficient transition region of the lower confinement layer 101 is formed between the first stray diffraction suppression lower confinement layer 101a and the second stray diffraction suppression lower confinement layer 101b, and the transition angle of the piezoelectric polarization coefficient transition region of the lower confinement layer 101 is 75°≤γ≤90°. Figure 12 As shown, a piezoelectric polarization coefficient transition region of the upper confinement layer 106 is formed between the first stray diffraction suppression spot upper confinement layer 106a and the second stray diffraction suppression spot upper confinement layer 106b, and the transition angle of the piezoelectric polarization coefficient transition region of the upper confinement layer 106 is 75°≤θ≤90°, and 75°≤θ≤γ≤90°.

[0030] In this embodiment, both the piezoelectric polarization coefficient distribution curves of the lower confinement layer 101 and the upper confinement layer 106 exhibit the Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution. This results in a steep piezoelectric polarization coefficient transition at the interfaces of the lower confinement layer 101a and the lower confinement layer 101b of the first stray diffraction-suppressed spot, as well as at the interfaces of the upper confinement layer 106a and the upper confinement layer 106b of the first stray diffraction-suppressed spot. This creates piezoelectric polarization coefficient distortion at the interfaces, generating a piezoelectric polarization stress birefringence gradient effect. This causes the interface between the upper confinement layer 106 and the lower confinement layer 101 to change from isotropic to anisotropic, resulting in wavefront distortion when lasers with different polarization directions propagate at the interface. This further suppresses spot diffraction diffusion and spot splitting, making the spot more compact, as... Figure 8 As shown.

[0031] In some optional embodiments, the first stray diffraction suppression layer 101a is any combination of GaN, AlGaN, and AlN, preferably Al. m Ga 1-m N (where 0.5% ≤ m ≤ 60%). The thickness of the confinement layer 101a under the first stray diffraction suppression spot is 50 nm to 5000 nm.

[0032] The second stray diffraction suppression lower confinement layer 101b is any combination of GaN, AlGaN, and AlN, preferably Al. n Ga 1-n N (where 2% ≤ n ≤ 80%). The thickness of the second stray diffraction suppression layer 101b is 50 nm to 8000 nm.

[0033] The confinement layer 106a on the first stray diffraction suppression spot is any combination of AlGaN, GaN, and AlN, preferably Al. p Ga 1-p N (where 0.5% ≤ p ≤ 60%).

[0034] The second stray diffraction suppression layer 106b on the confinement layer is any combination of AlGaN, GaN, and AlN, preferably Al. q Ga 1- q N (where 0%≤q≤50%).

[0035] In some alternative embodiments, substrate 100 is a GaN single-crystal substrate.

[0036] The lower waveguide layer 102 is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the lower waveguide layer 102 is from 300 angstroms to 8000 angstroms.

[0037] The active layer 103 is an InGaN / GaN quantum well.

[0038] The upper waveguide layer 104 is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the upper waveguide layer 104 is from 300 angstroms to 8000 angstroms.

[0039] The electron blocking layer 105 is any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, and the thickness of the electron blocking layer 105 is from 5 angstroms to 800 angstroms.

[0040] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A gallium nitride-based semiconductor laser with a stray diffraction suppression layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, and an upper confinement layer, characterized in that, The lower confinement layer includes a first stray diffraction spot lower confinement layer and a second stray diffraction spot lower confinement layer, wherein the first stray diffraction spot lower confinement layer is located below the second stray diffraction spot lower confinement layer; the upper confinement layer includes a first stray diffraction spot upper confinement layer and a second stray diffraction spot upper confinement layer, wherein the first stray diffraction spot upper confinement layer is located below the second stray diffraction spot upper confinement layer. The SIMS test Al atom concentration or Al ion intensity curve of the lower confinement layer, the refractive index distribution curve of the lower confinement layer, the SIMS test Al atom concentration or Al ion intensity curve of the upper confinement layer, the EDX test Al relative atomic intensity curve of the upper confinement layer, and the refractive index distribution curve of the upper confinement layer all have a Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution, where: y is the Al atom concentration or Al ion intensity of the SIMS test, x is the epitaxial layer thickness of the SIMS test, the starting point 0 is the epitaxial layer surface, A1 is the initial asymptotic value, A2 is the final asymptotic value, x0 is the midpoint, and dx is the rate of change parameter.

2. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, In the SIMS test Al atom concentration or Al ion intensity curve function of the lower confinement layer: 5E18≤A1≤5E21, 5E17≤A2≤5E20, 1≤x0≤6, 0.0002≤dx≤0.

2.

3. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, In the SIMS test Al atom concentration or Al ion intensity curve function of the upper confinement layer: 5E14≤A1≤5E18, 5E18≤A2≤5E21, 0.03≤x0≤3, 0.0001≤dx≤0.

1.

4. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, In the SIMS test Al atom concentration or Al ion intensity curve function of the lower confinement layer and the SIMS test Al atom concentration or Al ion intensity curve function of the upper confinement layer, the initial asymptotic value of the lower confinement layer is greater than or equal to the initial asymptotic value of the upper confinement layer, the final asymptotic value of the lower confinement layer is less than or equal to the final asymptotic value of the upper confinement layer, the midpoint of the lower confinement layer is greater than or equal to the midpoint of the upper confinement layer, the rate of change parameter of the lower confinement layer is greater than or equal to the rate of change parameter of the upper confinement layer, and 100≤lower confinement layer A1 / upper confinement layer A1≤5000, 0.05≤lower confinement layer A2 / upper confinement layer A2≤5, 1≤lower confinement layer x0 / upper confinement layer x0≤20, and 0.2≤lower confinement layer dx / upper confinement layer dx≤20.

5. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, The SIMS test Al atom concentration or Al ion intensity of the first stray diffraction suppression spot under the confinement layer is greater than or equal to the SIMS test Al atom concentration or Al ion intensity of the second stray diffraction suppression spot under the confinement layer.

6. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, In the Al relative atomic intensity curve function of the EDX test of the upper confinement layer: 0.05≤A1≤5, 0.5≤A2≤50, 50≤x0≤5000, 0.5≤dx≤50.

7. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, In the refractive index distribution curve function of the lower confinement layer: 1≤A1≤5, 1≤A2≤5, 1≤x0≤5, 0.0001≤dx≤0.1; In the refractive index distribution curve function of the upper confinement layer: 1≤A1≤5, 1≤A2≤5, 0.1≤x0≤1, 0.0001≤dx≤0.1; A lower confinement layer refractive index transition region is formed between the first lower confinement layer for suppressing stray diffraction spots and the second lower confinement layer for suppressing stray diffraction spots, wherein the transition angle of the lower confinement layer refractive index transition region is 75°≤α≤90°. An upper confinement layer refractive index transition region is formed between the first and second upper confinement layers of the stray diffraction suppression spot. The transition angle of the upper confinement layer refractive index transition region is 75°≤β≤90° and 75°≤β≤α≤90°.

8. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, Both the piezoelectric polarization coefficient distribution curve of the lower confinement layer and the piezoelectric polarization coefficient distribution curve of the upper confinement layer have the Boltzmann function y=A2+(A1-A2) / (1+exp((x-x0) / dx)) curve distribution; In the piezoelectric polarization coefficient distribution curve function of the lower confinement layer: 0.05≤A1≤5, 0.01≤A2≤5, 0.5≤x0≤10, 0.0002≤dx≤0.2; In the piezoelectric polarization coefficient distribution curve function of the upper confinement layer: 0.05≤A1≤5, 0.05≤A2≤5, 0.01≤x0≤5, 0.0001≤dx≤0.1; A transition region of the piezoelectric polarization coefficient of the lower confinement layer is formed between the first lower confinement layer for suppressing stray diffraction and the second lower confinement layer for suppressing stray diffraction. The transition angle of the piezoelectric polarization coefficient transition region of the lower confinement layer is 75°≤γ≤90°. A transition region of the piezoelectric polarization coefficient of the upper confinement layer is formed between the first and second piezoelectric polarization spots. The transition angle of the piezoelectric polarization coefficient transition region of the upper confinement layer is 75°≤θ≤90° and 75°≤θ≤γ≤90°.

9. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, The first stray diffraction suppression lower confinement layer is any combination of GaN, AlGaN, and AlN, and the thickness of the first stray diffraction suppression lower confinement layer is 50 nm to 5000 nm. The second confinement layer under the stray diffraction suppression spot is any combination of GaN, AlGaN, and AlN, and the thickness of the second confinement layer under the stray diffraction suppression spot is 50 nm to 8000 nm. The confinement layer on the first stray diffraction suppression spot is any combination of AlGaN, GaN, and AlN; The confinement layer on the second stray diffraction suppression spot is any combination of AlGaN, GaN, and AlN.

10. The gallium nitride-based semiconductor laser with a stray diffraction suppression layer according to claim 1, characterized in that, The substrate is a GaN single crystal substrate; The lower waveguide layer is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the lower waveguide layer is from 300 angstroms to 8000 angstroms. The active layer is an InGaN / GaN quantum well; The upper waveguide layer is any one of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, or GaN, and the thickness of the upper waveguide layer is from 300 angstroms to 8000 angstroms. The electron blocking layer is any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, and the thickness of the electron blocking layer is from 5 angstroms to 800 angstroms.

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