A laser with strain-modulated upper waveguide layer and a growth method thereof

Abstract

The present invention relates to a laser with a strain-modulated upper waveguide layer and a growth method thereof. The semiconductor laser comprises, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer, wherein the upper waveguide layer is a strain-modulated upper waveguide layer; the semiconductor laser forms a strain-modulated upper waveguide layer by regulating the peak electron drift rate distribution, deformation potential distribution, bulk elastic modulus distribution, and polarization optical phonon energy distribution of the upper waveguide layer, thereby suppressing spontaneous polarization and piezoelectric polarization effects, improving crystal quality, reducing non-radiative recombination, suppressing QCSE effects, reducing energy band tilt, and increasing the spatial overlap probability of electron-hole wave functions, thereby improving radiative recombination efficiency and reducing light absorption loss.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor optoelectronic devices, and in particular relates to a laser with a strain-modulated upper waveguide layer and a growth method thereof. Background Art

[0002] Lasers are widely used in laser display, laser TV, laser projector, communication, medical treatment, weapon, guidance, ranging, spectral analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and their classification methods are also diverse, mainly including solid, gas, liquid, semiconductor and dye types of 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 life, simple and compact structure, and miniaturization. There are major differences between lasers and nitride semiconductor light-emitting diodes: 1) Lasers are generated by stimulated radiation of carriers, with a small half-width of the spectrum and high brightness. The output power of a single laser can be in the W level, while nitride semiconductor light-emitting diodes are spontaneously radiated, and the output power of a single light-emitting diode is in the mW level; 2) The operating current density of the laser reaches KA / cm 2 , which is more than 2 orders of magnitude higher than that of nitride light-emitting diodes, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect, more serious electron-hole mismatch, and more serious efficiency attenuation Droop effect; 3) Light-emitting diodes spontaneously radiate incoherent light from high energy levels to low energy levels without external effects, while lasers radiate stimulated transitions. The energy of induced photons should be equal to the difference in energy levels of electron transitions, generating photons and induced photons that are completely coherent light; 4) Different principles: light-emitting diodes produce radiation recombination and luminescence under the action of external voltage when electron holes transition to quantum wells or pn junctions, while lasers require lasing conditions to be met before they can be lased. The carrier inversion distribution in the active region must be met. The stimulated radiation light oscillates back and forth in the resonant cavity, and the propagation in the gain medium amplifies the light. The threshold condition is met so that the gain is greater than the loss, and finally the laser is output.

[0003] Nitride semiconductor lasers have the following problems: crystal quality problems such as high defect density, high impurity concentration, and high stress, which restrict the improvement of laser performance and reliability; the lattice mismatch and large strain of the active layer induce a strong piezoelectric polarization effect, resulting in a strong QCSE quantum confined Stark effect, causing the energy band of the quantum well to tilt, the step difference of the laser valence band to increase, and the hole injection is suppressed. The hole transport in the quantum well is more difficult, the carrier injection is uneven, and the probability of electron-hole wave function overlap is reduced, which causes uneven laser gain and decreased radiation recombination efficiency, limiting the improvement of the laser's electro-lasing gain, resulting in limited output power of the laser, increased instability of the laser frequency, limited operating wavelength range of the laser, and affecting the signal-to-noise ratio and performance stability of the laser. Summary of the invention

[0004] The purpose of the present invention is to provide a semiconductor laser with simple structure and reasonable design in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A laser with a strain modulated upper waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer, wherein the upper waveguide layer is a strain modulated upper waveguide layer; and the strain modulated upper waveguide layer contains an In element;

[0007] The In element distribution of the strain modulated upper waveguide layer has a function y=log f ((h+x) / (hx)) The second three-quadrant curve distribution, where 0<f<1, and h>0.

[0008] As a further optimization scheme of the present invention, the strain modulated upper waveguide layer is any one or any combination of InGaN, InN, AlInGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, or any combination with GaN.

[0009] As a further optimization scheme of the present invention, the peak electron drift rate distribution of the strain modulated upper waveguide layer has an arc-shaped distribution;

[0010] The peak electron drift velocity distribution of the strain modulated upper waveguide layer has the function y=log a ((m+x) / (mx)) The second three-quadrant curve distribution, where 0<a<1, and m>0.

[0011] As a further optimization solution of the present invention, the deformation potential distribution of the strain modulated upper waveguide layer has an arc-shaped distribution;

[0012] The deformation potential distribution of the strain modulated upper waveguide layer has a function y=log b ((n+x) / (nx)) The second three-quadrant curve distribution, where b>1 and n>0.

[0013] As a further optimization scheme of the present invention, the volume elastic modulus distribution of the strain modulated upper waveguide layer has a function y=log c ((j+x) / (jx)) The second three-quadrant curve distribution, where c>1, and j>0.

[0014] As a further optimization scheme of the present invention, the polari-optical phonon energy distribution of the strain-modulated upper waveguide layer has a function y=log d ((k+x) / (kx)) The second three-quadrant curve distribution, where d>1, and k>0.

[0015] As a further optimization scheme of the present invention, the peak electron drift rate distribution, deformation potential distribution, bulk elastic modulus distribution, and polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the following relationship: 0<a<1<c≤b≤d.

[0016] As a further optimization scheme of the present invention, the In / C element ratio distribution of the strain modulated upper waveguide layer has a function y=log g ((u+x) / (ux)) The second three-quadrant curve distribution, where 0<g<1, and u>0;

[0017] The In / H element ratio distribution of the strain modulated upper waveguide layer has a function y=log p ((v+x) / (vx)) The second three-quadrant curve distribution, where 0<p<1, and v>0;

[0018] The In / O element ratio distribution of the strain modulated upper waveguide layer has a function y=log q ((w+x) / (wx)) The second three-quadrant curve distribution, where 0<q<1, w>0;

[0019] The In element distribution, In / C element ratio distribution, In / H element ratio distribution and In / O element ratio distribution of the strain-modulated upper waveguide layer have the following relationship: 0<p<g<q<f<1.

[0020] A single crystal growth method for producing the above-mentioned laser crystal with a strain-modulated upper waveguide layer, the method comprising the following steps:

[0021] S1, selecting a substrate material as a base film, and cleaning the film to remove pollutants on its surface;

[0022] S2, pre-treating the surface of the film, placing it on a substrate rack in a MOCVD reaction chamber, and evacuating the reaction chamber;

[0023] S3, introducing metal organic chemical gas precursor and carrier gas, and then preheating the film;

[0024] S4, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to first grow a lower confinement layer on the substrate;

[0025] S5, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to sequentially grow the lower waveguide layer and the active layer;

[0026] S6, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to grow the strain-modulated upper waveguide layer;

[0027] S7, epitaxially growing an upper confinement layer on the upper waveguide layer using MOCVD;

[0028] S8. After the growth is completed, the temperature of the reaction chamber is gradually lowered to allow the grown single crystal material to cool and solidify on the substrate. The substrate is taken out of the reaction chamber and subjected to subsequent processing to form a single crystal GaN-based semiconductor laser element.

[0029] As a further optimization scheme of the present invention, in step S4, the growth temperature of the lower confinement layer is 1000-1200°C, the growth pressure is 100-300 Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 1000~1300 rpm, the growth rate is 0.2~3um / h, the V / III ratio is 100~80000, and the doping element is SiH 4 or any one of disilane; in the step S5, the growth temperature of the lower waveguide layer is 650~1000℃, the growth pressure is 100~300Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 400~900 rpm, the growth rate is 0.05~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 Or any one of disilane, the growth temperature of the active layer is 600~950℃, the growth pressure is 100~250Torr, and the reaction elements are TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 300~800 rpm, the growth rate is 0.002~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 or any of disilane;

[0030] In step S6, the growth temperature of the strain modulated upper waveguide layer is 650-1000° C., the growth pressure is 100-300 Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH3 、N 2 , H 2 , the rotation speed is 400~900 rpm, the growth rate is 0.05~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 or any of disilane, by regulating the strain modulation of the In atoms injected into the upper waveguide layer with the function y = log f The second three-quadrant curve distribution of ((h+x) / (hx)) where 0<f<1 and h>0 makes the deformation potential distribution of the waveguide layer on the strain modulation have the function y=log b ((n+x) / (nx)) The second three-quadrant curve distribution, where b>1, and n>0; by adjusting the ratio of In / C atoms injected into the strain-modulated upper waveguide layer, y=log g The second three-quadrant curve distribution of ((u+x) / (ux)) where 0<g<1, and u>0, makes the peak electron drift velocity distribution of the strain modulated upper waveguide layer have the function y=log a ((m+x) / (mx)) The second three-quadrant curve distribution, where 0<a<1, and m>0; by adjusting the ratio of In / H atoms injected into the strain-modulated upper waveguide layer, y=log p The second three-quadrant curve distribution of ((v+x) / (vx)) where 0<p<1, and v>0, makes the bulk elastic modulus distribution of the strain-modulated waveguide layer have the function y=log c ((j+x) / (jx)) The second three-quadrant curve distribution, where c>1, and j>0; by adjusting the strain modulation of the In / O atomic ratio of the upper waveguide layer, the injection has y=log q The second three-quadrant curve distribution of ((w+x) / (wx)) where 0<q<1, w>0 makes the polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the function y=log d ((k+x) / (kx)) The second three-quadrant curve distribution, where d>1, and k>0.

[0031] The beneficial effects of the present invention are as follows: the present invention forms a strain-modulated upper waveguide layer by regulating the peak electron drift rate distribution, deformation potential distribution, volume elastic modulus distribution and polarization optical phonon energy distribution of the upper waveguide layer, thereby suppressing spontaneous polarization and piezoelectric polarization effects, improving crystal quality, reducing non-radiative recombination, suppressing QCSE effects, reducing energy band tilt, and increasing the spatial overlap probability of electron-hole wave functions, thereby improving radiative recombination efficiency and reducing light absorption losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1is a SIMS secondary ion mass spectrum of a laser with a strain-modulated upper waveguide layer according to an embodiment of the present invention;

[0033] Figure 2 is a schematic structural diagram of a laser with a strain-modulated upper waveguide layer according to an embodiment of the present invention;

[0034] Figure 3 The In atom implantation of the embodiment of the present invention has a function y=log f ((h+x) / (hx)) SIMS secondary ion mass spectrum of a laser with a strain-modulated upper waveguide layer distributed in the second three-quadrant curve;

[0035] Figure 4 In the embodiment of the present invention Figure 1 A partial enlarged view of a SIMS secondary ion mass spectrum of a laser with a strain-modulated upper waveguide layer;

[0036] Figure 5 This is a TEM transmission electron microscope image of a laser with a strain-modulated upper waveguide layer according to an embodiment of the present invention;

[0037] Figure 6 In the embodiment of the present invention Figure 5 A partial enlarged TEM image of a laser with a strain-modulated upper waveguide layer.

[0038] In the figure: 100, substrate; 101, lower confinement layer; 102, lower waveguide layer; 103, active layer; 104, upper waveguide layer; 105, upper confinement layer. DETAILED DESCRIPTION

[0039] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0040] like Figure 2 As shown, a laser with a strain modulated upper waveguide layer includes, 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, and an upper confinement layer 105, wherein the upper waveguide layer 104 is a strain modulated upper waveguide layer; and the strain modulated upper waveguide layer contains In element.

[0041] It should be noted that the spontaneous polarization and piezoelectric polarization effects are suppressed by strain modulating the upper waveguide layer, the crystal quality is improved, the non-radiative recombination is reduced, the QCSE effect is suppressed, the energy band tilt is reduced, and the spatial overlap probability of the electron-hole wave function is increased, thereby improving the radiative recombination efficiency and reducing the light absorption loss.

[0042] Further, such as Figure 5 As shown, the strain modulated upper waveguide layer is any one or any combination of InGaN, InN, AlInGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, or any combination with GaN.

[0043] Furthermore, the peak electron drift velocity distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution;

[0044] The peak electron drift velocity distribution of the strain modulated upper waveguide layer has the function y = log a ((m+x) / (mx)) The second three-quadrant curve distribution, where 0<a<1, and m>0.

[0045] It should be noted that the electron drift rate refers to the average moving speed of electrons in a conductor under the action of an electric field. By regulating the electric field shielding capability induced by the peak electrons of the upper waveguide layer 104 and the quantum well, the strain polarization field is offset, the polarization effect is reduced, the energy band steps and hole migration barriers of the upper waveguide layer 104 and the active layer 103 are reduced, electron leakage and uneven carrier injection are reduced, the process of stimulated radiation being greater than the loss is accelerated, and the threshold current density is reduced.

[0046] Furthermore, the deformation potential distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution;

[0047] The deformation potential distribution of the strain modulated waveguide layer has the function y = log b ((n+x) / (nx)) The second three-quadrant curve distribution, where b>1 and n>0.

[0048] Furthermore, the volume modulus distribution of the strain-modulated waveguide layer has the function y = log c ((j+x) / (jx)) The second three-quadrant curve distribution, where c>1, and j>0.

[0049] It should be noted that by regulating the deformation potential, bulk elastic modulus and change trend of the upper waveguide layer 104, the spontaneous polarization and piezoelectric polarization effects between the upper waveguide layer 104 and the active layer 103 are suppressed, the QCSE effect of the active layer 103 is suppressed, the energy band tilt is reduced, the spatial overlap probability and uniformity of the electron-hole wave function of the active layer 103 are improved, and the problems of poor interface crystal quality and high defect density caused by strain are improved, thereby improving the radiation recombination efficiency, laser power and gain uniformity, and laser life.

[0050] Furthermore, the energy distribution of polari-optical phonons in the strain-modulated upper waveguide layer has the function y = log d ((k+x) / (kx)) The second three-quadrant curve distribution, where d>1, and k>0.

[0051] It should be noted that the polarized optical phonon energy refers to the energy of phonons associated with the optical mode in the crystal. By regulating the phonon transport and distribution of the upper waveguide layer 104, the phonon scattering at the interface between the upper waveguide layer 104 and the active layer 103 is reduced, the heat generated by the Stokes frequency shift formed by the photon energy difference between the pump light and the oscillation light is reduced, the thermal stress and temperature distribution uniformity of the laser are reduced, and the optical catastrophe ratio of the laser is reduced.

[0052] Furthermore, the peak electron drift velocity distribution, deformation potential distribution, bulk elastic modulus distribution, and polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the following relationship: 0<a<1<c≤b≤d.

[0053] Further, such as Figure 1 and Figure 4 As shown, the In element distribution of the strain-modulated upper waveguide layer has a function y=log f ((h+x) / (hx)) The second three-quadrant curve distribution, where 0<f<1, and h>0;

[0054] like Figure 3 As shown, the In / C ratio distribution of the strain-modulated waveguide layer has a function y=log g ((u+x) / (ux)) The second three-quadrant curve distribution, where 0<g<1, and u>0;

[0055] like Figure 3 As shown, the In / H ratio distribution of the strain-modulated waveguide layer has a function y=log p ((v+x) / (vx)) The second three-quadrant curve distribution, where 0<p<1, and v>0;

[0056] like Figure 3 As shown, the In / O ratio distribution of the strain-modulated waveguide layer has a function y=log q ((w+x) / (wx)) The second three-quadrant curve distribution, where 0<q<1, w>0;

[0057] The In element distribution, In / C element ratio distribution, In / H element ratio distribution and In / O element ratio distribution of the strain-modulated upper waveguide layer have the following relationship: 0<p<g<q<f<1.

[0058] It should be noted that if Figure 6As shown, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, the number of periods is 3 ≥ m ≥ 1, and the well layer is GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga 2 O 3 , BN, diamond, any one or any combination thereof, with a thickness of 10 to 150 angstroms;

[0059] Barrier layers are GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAs N, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga 2 O 3 , BN, diamond, any one or any combination thereof, with a thickness of 10 to 200 angstroms;

[0060] like Figure 5 As shown, the lower confinement layer 101, the lower waveguide layer 102, and the upper confinement layer 105 are GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga 2 O 3 , BN, diamond, any one or any combination;

[0061] The substrate 100 is a single crystal substrate, which is sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO 2 Composite substrates, Mo, TiW, CuW, Cu, sapphire / AlN composite substrates, diamond, sapphire / SiN x , Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x / SiO 2 Composite substrate, magnesium aluminum spinel MgAl 2 O 4 、MgO、ZnO、ZrB 2 、LiAlO 2 and LiGaO 2 Any type of composite substrate.

[0062] The comparison data of the laser of the present invention and the traditional laser are shown in the following table:

[0063] project Conventional laser Laser of the present invention Range of change Optical catastrophe ratio (PPM) 21 6 -71% <![CDATA[Threshold current density (kA / cm 2 )]]> 2.14 0.87 -59% Optical power(W)@3A 4.7 5.9 26% Aging life (65℃@3A) 16000 23000 44%

[0064] It can be seen from the above table that, compared with the traditional laser, the optical catastrophe ratio of the laser of the present invention is reduced from 21PPM to 6PPM, a decrease of 71%, and the threshold current density is reduced from 2.14kA / cm 2 Reduced to 0.87kA / cm 2 , reduced by 59%, the optical power increased from 4.7W to 5.9W, increased by 26%, and the aging life increased from 16,000 to 23,000, increased by 44%.

[0065] Specifically, the laser element of the present invention is tested using a laser chip test device, wherein the laser element is designed with a ridge width of 45um, a cavity length of 1200um, a test current of 0~4A ampere pulse or continuous mode test, a test environment temperature of 25°C, and then the laser light power signal is collected by an integrating sphere to test the light power and threshold current density (the threshold current density is the starting current density of the laser lasing);

[0066] When performing the aging life test, the sample is placed in an oven for aging test, where the aging temperature is 65°C and the aging current is 3A, and then the optical power attenuation at different aging times is tested.

[0067] It should be noted that the optical catastrophe ratio refers to the deviation or distortion caused by the imperfect shape or arrangement of optical elements when light passes through the optical system. Reducing the optical catastrophe ratio can improve the quality of the image and reduce the distortion of the incident light beam by the optical system, thereby improving the imaging resolution and enabling the system to more accurately distinguish subtle details and structures.

[0068] The increase in aging life means that the product is more stable and reliable during use, and the required maintenance and servicing costs will be reduced. Long-life lasers can extend their service life, extend the product replacement cycle, bring longer-term use value, and reduce overall costs, including maintenance costs, replacement costs, and environmental costs.

[0069] A single crystal growth method for a laser having a strain modulated upper waveguide layer, the method comprising the following steps:

[0070] S1, selecting a substrate material as a base film, and cleaning the film to remove pollutants on its surface;

[0071] S2, pre-treating the surface of the film, placing it on a substrate rack in a MOCVD reaction chamber, and evacuating the reaction chamber;

[0072] S3, introducing metal organic chemical gas precursor and carrier gas, and then preheating the film;

[0073] S4, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to first grow a lower confinement layer on the substrate;

[0074] S5, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to sequentially grow the lower waveguide layer and the active layer;

[0075] S6, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to grow the strain-modulated upper waveguide layer;

[0076] S7, epitaxially growing an upper confinement layer on the upper waveguide layer using MOCVD;

[0077] S8. After the growth is completed, the temperature of the reaction chamber is gradually lowered to allow the grown single crystal material to cool and solidify on the substrate. The substrate is taken out of the reaction chamber and subjected to subsequent processing to form a single crystal GaN-based semiconductor laser element.

[0078] Furthermore, in step S4, the growth temperature of the lower confinement layer 101 is 1000-1200°C, the growth pressure is 100-300 Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 1000~1300 rpm, the growth rate is 0.2~3um / h, the V / III ratio is 100~80000, and the doping element is SiH 4 or any one of disilane; further, in step S5, the growth temperature of the lower waveguide layer 102 is 650~1000℃, the growth pressure is 100~300Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH 3 、N 2 , H 2, the rotation speed is 400~900 rpm, the growth rate is 0.05~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 or disilane, the growth temperature of the active layer 103 is 600-950°C, the growth pressure is 100-250 Torr, and the reaction elements are TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 300~800 rpm, the growth rate is 0.002~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 or any of disilane;

[0079] In step S6, the growth temperature of the strain modulated upper waveguide layer is 650-1000°C, the growth pressure is 100-300 Torr, and the reaction elements are TMGa, TEGa, TMAl, TMIn, NH 3 、N 2 , H 2 , the rotation speed is 400~900 rpm, the growth rate is 0.05~2um / h, the V / III ratio is 1000~90000, and the doping element is SiH 4 or any of disilane;

[0080] like Figure 1 and Figure 4 As shown, the In atom injection into the upper waveguide layer by regulating the strain has the function y=log f The second three-quadrant curve distribution of ((h+x) / (hx)) where 0<f<1 and h>0 makes the deformation potential distribution of the waveguide layer on the strain modulation have the function y=log b The second and third quadrant curves of ((n+x) / (nx)) are distributed, where b>1 and n>0, and the deformation potential and change trend of the upper waveguide layer are further regulated to suppress the spontaneous polarization and piezoelectric polarization effects between the upper waveguide layer and the active layer, suppress the QCSE effect of the active layer, reduce the energy band tilt, improve the spatial overlap probability and uniformity of the electron-hole wave function of the active layer, and improve the problems of poor interface crystal quality and high defect density caused by strain, thereby improving the radiation recombination efficiency, laser power and gain uniformity, and laser life.

[0081] like Figure 3 As shown, by adjusting the strain modulation of the In / C atomic ratio of the upper waveguide layer, the injection has y=log g The second three-quadrant curve distribution of ((u+x) / (ux)) where 0<g<1 and u>0 makes the peak electron drift rate distribution of the strain-modulated upper waveguide layer have the function y=log a((m+x) / (mx)) second and third quadrant curve distribution, where 0<a<1, and m>0; further regulate the peak electron drift rate distribution of the strain-modulated upper waveguide layer, thereby regulating the electric field shielding ability of the peak electron induced by the upper waveguide layer and the quantum well, offsetting the strain polarization field, reducing the polarization effect, reducing the energy band order and hole migration barrier of the upper waveguide layer and the active layer, reducing electron leakage and uneven carrier injection, accelerating the process of stimulated radiation being greater than the loss, and reducing the threshold current density;

[0082] like Figure 3 As shown, by adjusting the strain modulation of the In / H atomic ratio of the upper waveguide layer, the injection has y=log p The second three-quadrant curve distribution of ((v+x) / (vx)) where 0<p<1, and v>0, makes the bulk elastic modulus distribution of the strain-modulated waveguide layer have the function y=log c ((j+x) / (jx)) second and third quadrant curve distribution, where c>1, and j>0; further control the volume elastic modulus and change trend of the upper waveguide layer, so as to suppress the spontaneous polarization and piezoelectric polarization effect between the upper waveguide layer and the active layer, suppress the QCSE effect of the active layer, reduce the energy band tilt, improve the spatial overlap probability and uniformity of the electron-hole wave function of the active layer, and improve the problems of poor interface crystal quality and high defect density caused by strain, thereby improving the radiation recombination efficiency, laser power and gain uniformity, and laser life;

[0083] like Figure 3 As shown, by adjusting the strain modulation of the In / O atomic ratio of the upper waveguide layer, the injection has y=log q The second third quadrant curve distribution of ((w+x) / (wx)) where 0<q<1, w>0 makes the polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the function y=log d ((k+x) / (kx)) second and third quadrant curve distribution, where d>1, and k>0; further regulate the polarization optical phonon energy distribution of the strain-modulated upper waveguide layer, and modulate the phonon transport and distribution of the upper waveguide layer, so as to reduce the phonon scattering at the interface between the upper waveguide layer and the active layer, reduce the heat generated by the Stokes frequency shift formed by the photon energy difference between the pump light and the oscillation light, reduce the thermal stress and temperature distribution uniformity of the laser, and reduce the optical catastrophe ratio of the laser.

[0084] It should be noted that MOCVD is a new type of vapor phase epitaxial growth technology developed on the basis of vapor phase epitaxy (VPE). Specifically, MOCVD uses organic compounds of group III and group II elements and hydrides of group V and VI elements as crystal growth source materials, and performs vapor phase epitaxy on a substrate in the form of a thermal decomposition reaction to grow thin-layer single crystal materials of various group III-V, group II-VI compound semiconductors and their multi-component solid solutions.

[0085] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A laser having a strain-modulated upper waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer, characterized in that: The upper waveguide layer is a strain modulated upper waveguide layer; the strain modulated upper waveguide layer contains In element; The In element distribution of the strain modulated upper waveguide layer has a function y=log f ((h+x) / (hx)) The second three-quadrant curve distribution, where 0<f<1, and h>0, where x is the depth of the strain-modulated upper waveguide layer; The strain modulated upper waveguide layer is any one or any combination of InGaN, InN, AlInGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, or any combination of GaN and GaN.

2. A laser with a strain-modulated upper waveguide layer according to claim 1, characterized in that: The peak electron drift velocity distribution of the strain modulated upper waveguide layer has an arc-shaped distribution; The peak electron drift velocity distribution of the strain modulated upper waveguide layer has the function y=log a ((m+x) / (mx)) The second three-quadrant curve distribution, where 0<a<1, and m>0.

3. The laser with a strain-modulated upper waveguide layer according to claim 2, characterized in that: The deformation potential distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution; The deformation potential distribution of the strain modulated upper waveguide layer has a function y=log b ((n+x) / (nx)) The second three-quadrant curve distribution, where b>1 and n>0.

4. The laser with a strain-modulated upper waveguide layer according to claim 3, characterized in that: The bulk elastic modulus distribution of the strain modulated upper waveguide layer has a function y=log c ((j+x) / (jx)) The second three-quadrant curve distribution, where c>1, and j>0.

5. The laser with a strain-modulated upper waveguide layer according to claim 4, characterized in that: The polari-optical phonon energy distribution of the strain-modulated upper waveguide layer has the function y=log d ((k+x) / (kx)) The second three-quadrant curve distribution, where d>1, and k>0.

6. The laser with a strain-modulated upper waveguide layer according to claim 5, characterized in that: The peak electron drift rate distribution, deformation potential distribution, bulk elastic modulus distribution, and polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the following relationship: 0<a<1<c≤b≤d.

7. The laser with a strain-modulated upper waveguide layer according to claim 1, characterized in that: The In / C element ratio distribution of the strain modulated upper waveguide layer has a function y=log g ((u+x) / (ux)) The second three-quadrant curve distribution, where 0<g<1, and u>0; The In / H element ratio distribution of the strain modulated upper waveguide layer has a function y=log p ((v+x) / (vx)) The second three-quadrant curve distribution, where 0<p<1, and v>0; The In / O element ratio distribution of the strain modulated upper waveguide layer has a function y=log q ((w+x) / (wx)) The second three-quadrant curve distribution, where 0<q<1, w>0; The In element distribution, In / C element ratio distribution, In / H element ratio distribution and In / O element ratio distribution of the strain-modulated upper waveguide layer have the following relationship: 0<p<g<q<f<1.

8. A single crystal growth method for growing a crystal of a laser having a strain modulated upper waveguide layer as claimed in any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1, selecting a substrate material as a base film, and cleaning the film to remove pollutants on its surface; S2, pre-treating the surface of the film, placing it on a substrate rack in a MOCVD reaction chamber, and evacuating the reaction chamber; S3, introducing metal organic chemical gas precursor and carrier gas, and then preheating the film; S4, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to first grow a lower confinement layer on the substrate; S5, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to sequentially grow the lower waveguide layer and the active layer; S6, regulating the set temperature, pressure, reaction element selection and ratio, rotation speed, growth rate, V / III ratio, and combination of doping elements to grow the strain-modulated upper waveguide layer; S7, epitaxially growing an upper confinement layer on the upper waveguide layer using MOCVD; S8, after the growth is completed, gradually lowering the temperature of the reaction chamber to cool the grown single crystal material and solidify it on the substrate, taking the substrate out of the reaction chamber and performing subsequent processing to form a single crystal GaN-based semiconductor laser element; In the step S4, the growth temperature of the lower limiting layer is 1000-1200°C, the growth pressure is 100-300Torr, the reaction elements are TMGa, TEGa, TMAl, TMIn, NH3, N2, H2, the rotation speed is 1000-1300 rpm, the growth rate is 0.2-3um / h, the V / III ratio is 100-80000, and the doping element is any one of SiH4 and disilane; in the step S5, the growth temperature of the lower waveguide layer is 650-1000°C, the growth pressure is 100-300Torr, the reaction elements are TMGa, TEGa, TMAl , TMIn, NH3, N2, H2, the rotation speed is 400~900 rpm, the growth rate is 0.05~2um / h, the V / III ratio is 1000~90000, the doping element is any one of SiH4 or disilane, the growth temperature of the active layer is 600~950℃, the growth pressure is 100~250Torr, the reaction elements are TEGa, TMAl, TMIn, NH3, N2, H2, the rotation speed is 300~800 rpm, the growth rate is 0.002~2um / h, the V / III ratio is 1000~90000, and the doping element is any one of SiH4 or disilane; In the step S6, the growth temperature of the strain modulated upper waveguide layer is 650-1000° C., the growth pressure is 100-300 Torr, the reaction elements are TMGa, TEGa, TMAl, TMIn, NH3, N2, H2, the rotation speed is 400-900 rpm, the growth rate is 0.05-2 um / h, the V / III ratio is 1000-90000, and the doping element is any one of SiH4 or disilane. By regulating the In atomic injection of the strain modulated upper waveguide layer, the function y=log f The second three-quadrant curve distribution of ((h+x) / (hx)) where 0<f<1 and h>0 makes the deformation potential distribution of the waveguide layer on the strain modulation have the function y=log b ((n+x) / (nx)) The second three-quadrant curve distribution, where b>1, and n>0; by adjusting the ratio of In / C atoms injected into the strain-modulated upper waveguide layer, y=log g The second three-quadrant curve distribution of ((u+x) / (ux)) where 0<g<1, and u>0, makes the peak electron drift velocity distribution of the strain modulated upper waveguide layer have the function y=log a ((m+x) / (mx)) The second three-quadrant curve distribution, where 0<a<1, and m>0; by adjusting the ratio of In / H atoms injected into the strain-modulated upper waveguide layer, y=log p The second three-quadrant curve distribution of ((v+x) / (vx)) where 0<p<1, and v>0, makes the bulk elastic modulus distribution of the strain-modulated waveguide layer have the function y=log c ((j+x) / (jx)) The second three-quadrant curve distribution, where c>1, and j>0; by adjusting the strain modulation of the In / O atomic ratio of the upper waveguide layer, the injection has y=log q The second three-quadrant curve distribution of ((w+x) / (wx)) where 0<q<1, w>0 makes the polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the function y=log d ((k+x) / (kx)) The second three-quadrant curve distribution, where d>1, and k>0.

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