Gallium nitride-based semiconductor laser chip

Abstract

The gallium nitride-based semiconductor laser chip comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper coating layer which are sequentially arranged from bottom to top, and the upper waveguide layer has a dielectric constant distribution characteristic and a heat conductivity distribution characteristic. Specific dielectric constant distribution characteristics and heat conductivity distribution characteristics are set in the upper waveguide layer of the gallium nitride-based semiconductor laser chip, and the dielectric constant and the heat conductivity of the upper waveguide layer are designed to be changed towards the angles of the active layer and the upper coating layer. The heat loss caused by the energy loss with the coupling rate of not 1 from the pumping energy level to the laser upper energy level is reduced, the Joule heat loss is reduced, the temperature uniformity and the thermal stress distribution uniformity of the laser are improved, and the thermal lens effect and the stress birefringence effect are reduced, so that the depolarization and distortion of laser beams are reduced, and the laser quality is improved. And the far-field FFP image quality and the light spot output are improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor optoelectronic devices, and in particular to a gallium nitride-based semiconductor laser chip. Background Art

[0002] Lasers are widely used in laser display, laser TV, laser projector, communication, medical treatment, weapons, guidance, ranging, spectral analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and the 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.

[0003] There are big differences between lasers and nitride semiconductor light-emitting diodes:

[0004] 1) Laser is generated by stimulated radiation of carriers, the spectrum half-width is small, the brightness is very high, and 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;

[0005] 2) The current density of the laser reaches KA / cm2, 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;

[0006] 3) The spontaneous transition radiation of the light-emitting diode is incoherent light that transitions from a high energy level to a low energy level without any external influence, while the laser is stimulated transition radiation, and the energy of the induced photon should be equal to the difference in the energy level of the electron transition, producing the same coherent light as the photon and the induced photon;

[0007] 4) Different principles: When an external voltage is applied to a light-emitting diode, electron holes jump to a quantum well or a pn junction to generate radiative recombination light, while a laser can only emit when the lasing conditions are met. The carrier distribution in the active region must be reversed, and the stimulated radiation light oscillates back and forth in the resonant cavity. The propagation in the gain medium amplifies the light, and the threshold condition is met so that the gain is greater than the loss, and finally the laser is output.

[0008] Nitride semiconductor lasers have the following problems: the Stokes shift loss formed by the photon energy difference between the pump light and the oscillating light is converted into heat, and the energy loss from the pump energy level to the upper laser energy level is not 1. The two together produce a large amount of waste heat, which makes the temperature distribution of the laser uneven, causing thermal expansion and uneven distribution of thermal stress, resulting in thermal lens effect and stress birefringence effect; the thermal lens produces a lens-like phenomenon in space, and the stress birefringence effect changes the polarization state of the incident light, causing the laser beam to depolarize and distort. The Stokes shift loss formed by the photon energy difference between the pump light and the oscillating light is converted into heat, and the energy loss from the pump energy level to the upper laser energy level is not 1. The two together produce a large amount of waste heat, which makes the temperature distribution of the laser uneven, causing thermal expansion and uneven distribution of thermal stress, resulting in temperature quenching, laser breakage, thermal lens effect and stress birefringence effect; the thermal lens produces a lens-like phenomenon in space, and the stress birefringence effect changes the polarization state of the incident light, causing the laser beam to depolarize and distort. There are non-radiative recombination losses and free carrier absorption in the active area of ​​the laser chip, which generate a lot of heat. At the same time, the resistance of the epitaxial and chip materials will produce Joule heat loss and carrier absorption loss under current injection. The chip material has low thermal conductivity and poor heat dissipation performance, which leads to the increase of active layer temperature, red shift of lasing wavelength, decrease of quantum efficiency, reduction of power, increase of threshold current, shortened life and deterioration of reliability. Summary of the invention

[0009] In order to solve one of the above technical problems, the present invention provides a gallium nitride-based semiconductor laser chip.

[0010] An embodiment of the present invention provides a gallium nitride-based semiconductor laser chip, comprising a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper cladding layer arranged in sequence from bottom to top, wherein the upper waveguide layer has a dielectric constant distribution characteristic and a thermal conductivity distribution characteristic;

[0011] The descending angle of the peak position of the dielectric constant of the upper waveguide layer toward the upper cladding layer is α, and the rising angle of the valley position of the dielectric constant of the upper waveguide layer toward the active layer is β, wherein: 10°≤α≤β≤90°;

[0012] The rising angle of the valley position of the thermal conductivity of the upper waveguide layer toward the upper cladding layer is γ, and the descending angle of the peak position of the thermal conductivity of the upper waveguide layer toward the active layer is θ, wherein: 25°≤γ≤θ≤90°.

[0013] Preferably, the descending angle of the peak position of the dielectric constant of the upper waveguide layer toward the upper cladding layer, the rising angle of the valley position of the dielectric constant of the upper waveguide layer toward the active layer, the rising angle of the valley position of the thermal conductivity of the upper waveguide layer toward the upper cladding layer, and the descending angle of the peak position of the thermal conductivity of the upper waveguide layer toward the active layer have the following relationship: 10°≤α≤β≤γ≤θ≤90°.

[0014] Preferably, the upper waveguide layer also has polarization optical phonon energy distribution characteristics, longitudinal phonon velocity distribution characteristics, peak electron drift velocity distribution characteristics and bulk elastic modulus distribution characteristics;

[0015] The rising angle of the valley position of the polarized optical phonon energy of the upper waveguide layer toward the upper cladding layer is δ;

[0016] The rising angle of the valley position of the longitudinal phonon velocity of the upper waveguide layer toward the upper cladding layer is σ;

[0017] The peak position of the peak electron drift rate of the upper waveguide layer decreases at an angle of φ toward the upper cladding layer;

[0018] The rising angle of the valley position of the bulk elastic modulus of the upper waveguide layer toward the upper cladding layer is ρ;

[0019] Among them: 5°≤δ≤σ≤φ≤ρ≤90°.

[0020] Preferably, the peak position of the polarized optical phonon energy of the upper waveguide layer decreases at an angle ψ toward the active layer;

[0021] The decreasing angle of the peak position of the longitudinal phonon velocity of the upper waveguide layer toward the active layer is μ;

[0022] The rising angle of the valley position of the peak electron drift velocity of the upper waveguide layer toward the active layer is υ;

[0023] The peak position of the bulk elastic modulus of the upper waveguide layer decreases at an angle ω toward the active layer;

[0024] Among them: 10°≤ψ≤μ≤υ≤ω≤90°.

[0025] Preferably, the polarization-optical phonon energy, longitudinal phonon velocity, and the rising angle of the valley position of the bulk elastic modulus of the upper waveguide layer toward the upper cladding layer, the decreasing angle of the peak position of the peak electron drift velocity of the upper waveguide layer toward the upper cladding layer, the polarization-optical phonon energy, longitudinal phonon velocity, and the peak position of the bulk elastic modulus of the upper waveguide layer toward the active layer, and the rising angle of the valley position of the peak electron drift velocity of the upper waveguide layer toward the active layer have the following relationship: 5°≤δ≤σ≤φ≤ρ≤ψ≤μ≤υ≤ω≤90°.

[0026] Preferably, the upper waveguide layer is any one or any combination of InGaN, GaN, InN, AlInGaN, AlInN, and has a thickness of 10 nm to 1000 nm.

[0027] Preferably, the dielectric constant of the upper waveguide layer has the function y1=A+Blog a ((m+x) / (mx)) The fourth quadrant curve distribution, and 0<a<1, m>0;

[0028] The thermal conductivity of the upper waveguide layer has the function y2=C+Dlog b ((n+x) / (nx)) The second quadrant curve distribution, and b>1, n>0;

[0029] Wherein, x is the depth of the upper waveguide layer toward the electron blocking layer, C≤A.

[0030] Preferably, the polarized optical phonon energy of the upper waveguide layer has a function y3=E+Farccscx curve distribution;

[0031] The longitudinal phonon velocity of the upper waveguide layer has a first quadrant curve distribution of function y4=G+Hx / lnx;

[0032] The bulk elastic modulus of the upper waveguide layer has the function y5=J+Ksinx / x 2 The first quadrant curve distribution;

[0033] The peak electron drift velocity of the upper waveguide layer has the function y6=L+M(c x +1) / (c x -1) The first quadrant curve distribution, and 0<c<1;

[0034] Wherein, x is the depth of the upper waveguide layer toward the electron blocking layer, E≤J≤G≤L.

[0035] Preferably, the active layer is a periodic structure consisting of a well layer and a barrier layer;

[0036] The well layer of the active layer is any one or any combination of 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, Ga2O3, BN, and diamond, and has a thickness of 10 angstroms to 100 angstroms;

[0037] The barrier layer of the active layer is any one or any combination of 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, Ga2O3, BN, and diamond, and has a thickness of 10 to 200 angstroms.

[0038] Preferably, the lower cladding layer, the lower waveguide layer, the electron blocking layer and the upper cladding layer are any one or any combination of 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, Ga2O3, BN and diamond;

[0039] The substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, graphene, sapphire / SiN x , Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0040] The beneficial effects of the present invention are as follows: the present invention sets specific dielectric constant distribution characteristics and thermal conductivity distribution characteristics in the upper waveguide layer of the gallium nitride-based semiconductor laser chip, and reduces the heat loss caused by the energy loss when the coupling rate from the pump energy level to the upper energy level of the laser is not 1 by designing the angle change of the dielectric constant and thermal conductivity of the upper waveguide layer toward the active layer and the upper cladding layer, reduces the Joule heat loss, improves the temperature uniformity and thermal stress distribution uniformity of the laser, reduces the thermal lens effect and stress birefringence effect, thereby reducing the depolarization and distortion of the laser beam, improving the far-field FFP image quality and improving the spot output. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0042] Figure 1 This is a schematic structural diagram of a gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0043] Figure 2 This is a SIMS secondary ion mass spectrum of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0044] Figure 3 A locally enlarged SIMS secondary ion mass spectrum of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0045] Figure 4 This is a TEM lens electron microscope image of the upper waveguide layer of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0046] Figure 5 This is a TEM lens electron microscope image of the lower waveguide layer of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0047] Figure 6 This is a TEM lens electron microscope image of the active layer of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0048] Figure 7 This is a TEM lens electron microscope image of the electron blocking layer of the gallium nitride-based semiconductor laser chip according to an embodiment of the present invention;

[0049] Figure 8 This is a TEM lens electron microscope image of the upper cladding layer of the gallium nitride-based semiconductor laser chip described in an embodiment of the present invention.

[0050] Reference numerals:

[0051] 100. substrate, 101. lower cladding layer, 102. lower waveguide layer, 103. active layer, 104. upper waveguide layer, 105. electron blocking layer, 106. upper cladding layer. DETAILED DESCRIPTION

[0052] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0053] like Figures 1 to 8 As shown, this embodiment provides a gallium nitride-based semiconductor laser chip, including a substrate 100, a lower cladding layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105 and an upper cladding layer 106 arranged in sequence from bottom to top.

[0054] Specifically, in this embodiment, the gallium nitride-based semiconductor laser chip is provided with a substrate 100, a lower cladding layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105 and an upper cladding layer 106 in sequence from top to bottom, wherein the upper waveguide layer 104 is a thermally conductive enhanced upper waveguide layer.

[0055] In this embodiment, the upper waveguide layer 104 has a dielectric constant distribution characteristic and a thermal conductivity distribution characteristic, and the dielectric constant and thermal conductivity in the upper waveguide layer 104 show a certain change trend toward the active layer 103 and the upper cladding layer 106, which is specifically shown as follows:

[0056] The peak position of the dielectric constant of the upper waveguide layer 104 shows a decreasing trend toward the upper cladding layer 106;

[0057] The valley position of the dielectric constant of the upper waveguide layer 104 shows an upward trend toward the active layer 103;

[0058] Specifically, the peak position of the dielectric constant of the upper waveguide layer 104 has a decreasing angle α toward the upper cladding layer 106 , and the valley position of the dielectric constant of the upper waveguide layer 104 has a rising angle β toward the active layer 103 , wherein: 10°≤α≤β≤90°.

[0059] The valley position of the thermal conductivity of the upper waveguide layer 104 shows an upward trend toward the upper cladding layer 106;

[0060] The peak position of the thermal conductivity of the upper waveguide layer 104 shows a downward trend toward the active layer 103;

[0061] Specifically, the rising angle of the valley position of the thermal conductivity of the upper waveguide layer 104 toward the upper cladding layer 106 is γ, and the falling angle of the peak position of the thermal conductivity of the upper waveguide layer 104 toward the active layer 103 is θ, wherein: 25°≤γ≤θ≤90°.

[0062] Among them, the descending angle of the peak position of the dielectric constant of the upper waveguide layer 104 toward the upper cladding layer 106, the rising angle of the valley position of the dielectric constant of the upper waveguide layer 104 toward the active layer 103, the rising angle of the valley position of the thermal conductivity of the upper waveguide layer 104 toward the upper cladding layer 106, and the descending angle of the peak position of the thermal conductivity of the upper waveguide layer 104 toward the active layer 103 have the following relationship: 10°≤α≤β≤γ≤θ≤90°.

[0063] In this embodiment, specific dielectric constant distribution characteristics and thermal conductivity distribution characteristics are set in the upper waveguide layer 104 of the gallium nitride-based semiconductor laser chip. By designing the angular changes of the dielectric constant and thermal conductivity of the upper waveguide layer 104 toward the active layer 103 and the upper cladding layer 106, the heat loss caused by the energy loss when the coupling rate from the pump energy level to the upper laser energy level is not 1 is reduced, the Joule heat loss is reduced, the temperature uniformity and thermal stress distribution uniformity of the laser are improved, the thermal lens effect and the stress birefringence effect are reduced, thereby reducing the depolarization and distortion of the laser beam, improving the far-field FFP image quality and improving the spot output.

[0064] In some optional embodiments, the upper waveguide layer 104 further has polarization optical phonon energy distribution characteristics, longitudinal phonon velocity distribution characteristics, peak electron drift velocity distribution characteristics and bulk elastic modulus distribution characteristics, and the polarization optical phonon energy, longitudinal phonon velocity, peak electron drift velocity and bulk elastic modulus of the upper waveguide layer 104 show a certain change trend toward the upper cladding layer 106 and the active layer 103, which are specifically manifested as follows:

[0065] The valley position of the polarized optical phonon energy of the upper waveguide layer 104 shows an upward trend toward the upper cladding layer 106;

[0066] The valley position of the longitudinal phonon velocity of the upper waveguide layer 104 shows an upward trend toward the upper cladding layer 106;

[0067] The peak position of the peak electron drift velocity of the upper waveguide layer 104 shows a decreasing trend toward the upper cladding layer 106;

[0068] The valley position of the bulk elastic modulus of the upper waveguide layer 104 shows an upward trend toward the upper cladding layer 106;

[0069] Specifically, the rising angle of the valley position of the polarization optical phonon energy of the upper waveguide layer 104 toward the upper cladding layer 106 is δ, the rising angle of the valley position of the longitudinal phonon velocity of the upper waveguide layer 104 toward the upper cladding layer 106 is σ, the falling angle of the peak position of the peak electron drift velocity of the upper waveguide layer 104 toward the upper cladding layer 106 is φ, and the rising angle of the valley position of the bulk elastic modulus of the upper waveguide layer 104 toward the upper cladding layer 106 is ρ, wherein: 5°≤δ≤σ≤φ≤ρ≤90°.

[0070] The peak position of the polarized optical phonon energy of the upper waveguide layer 104 shows a downward trend toward the active layer 103;

[0071] The peak position of the longitudinal phonon velocity of the upper waveguide layer 104 shows a downward trend toward the active layer 103;

[0072] The valley position of the peak electron drift velocity of the upper waveguide layer 104 shows an upward trend toward the active layer 103;

[0073] The peak position of the bulk elastic modulus of the upper waveguide layer 104 shows a downward trend toward the active layer 103;

[0074] Specifically, the peak position of the polarization-optical phonon energy of the upper waveguide layer 104 has a decreasing angle of ψ toward the active layer 103, the peak position of the longitudinal phonon velocity of the upper waveguide layer 104 has a decreasing angle of μ toward the active layer 103, the valley position of the peak electron drift velocity of the upper waveguide layer 104 has a rising angle of υ toward the active layer 103, and the peak position of the bulk elastic modulus of the upper waveguide layer 104 has a decreasing angle of ω toward the active layer 103, wherein: 10°≤ψ≤μ≤υ≤ω≤90°.

[0075] Among them, the polarization-optical phonon energy, the longitudinal phonon velocity, the rising angle of the valley position of the bulk elastic modulus of the upper waveguide layer 104 toward the upper cladding layer 106, the decreasing angle of the peak position of the peak electron drift velocity of the upper waveguide layer 104 toward the upper cladding layer 106, the decreasing angle of the polarization-optical phonon energy, the longitudinal phonon velocity, the peak position of the bulk elastic modulus of the upper waveguide layer 104 toward the active layer 103, and the rising angle of the valley position of the peak electron drift velocity of the upper waveguide layer 104 toward the active layer 103 have the following relationship: 5°≤δ≤σ≤φ≤ρ≤ψ≤μ≤υ≤ω≤90°.

[0076] This embodiment reduces the heat loss caused by the energy loss when the coupling rate from the pump energy level to the upper energy level of the laser is not 1, reduces the Joule heat loss, improves the temperature uniformity and thermal stress distribution uniformity of the laser, reduces the thermal lens effect and stress birefringence effect, thereby reducing the depolarization and distortion of the laser beam, improving the far-field FFP image quality and improving the spot output. At the same time, the peak electron drift rate of the upper waveguide layer 104, the descending angle of the peak position of the dielectric constant toward the upper cladding layer 106, and the rising angle of the valley position toward the active layer 103 are regulated to reduce stray light and leakage light, improve the horizontal expansion angle of the laser, improve the stability of the transverse mode and reduce the inter-mode variation of the longitudinal mode, suppress the leakage of the light field mode, achieve a low aspect ratio FFP far-field image and reduce the focus spot size.

[0077] In some optional embodiments, the upper waveguide layer 104 is any one or any combination of InGaN, GaN, InN, AlInGaN, and AlInN, and has a thickness of 10 nm to 1000 nm.

[0078] In some optional embodiments, the distribution of dielectric constant, thermal conductivity, polarimetric phonon energy, longitudinal phonon velocity, bulk elastic modulus, and peak electron drift velocity in the upper waveguide layer 104 is as follows:

[0079] The dielectric constant of the upper waveguide layer 104 has the function y1=A+Blog a ((m+x) / (mx)) The fourth quadrant curve distribution, and 0<a<1, m>0;

[0080] The thermal conductivity of the upper waveguide layer 104 has the function y2=C+Dlog b ((n+x) / (nx)) The second quadrant curve distribution, and b>1, n>0;

[0081] The polarized optical phonon energy of the upper waveguide layer 104 has a function y3=E+Farccscx curve distribution;

[0082] The longitudinal phonon velocity of the upper waveguide layer 104 has a first quadrant curve distribution of the function y4=G+Hx / lnx;

[0083] The bulk modulus of the upper waveguide layer 104 has the function y5=J+Ksinx / x 2 The first quadrant curve distribution;

[0084] The peak electron drift velocity of the upper waveguide layer 104 has the function y6=L+M(c x +1) / (cx -1) The first quadrant curve distribution, and 0<c<1;

[0085] Wherein, x is the depth of the upper waveguide layer 104 toward the electron blocking layer 105 , C≤A, E≤J≤G≤L.

[0086] In some optional embodiments, the active layer 103 is a periodic structure consisting of a well layer and a barrier layer.

[0087] Specifically, the well layer of the active layer 103 is any one or any combination of 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, Ga2O3, BN, and diamond, and the thickness is 10 to 100 angstroms.

[0088] The barrier layer of the active layer 103 is any one or any combination of 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, Ga2O3, BN, and diamond, and has a thickness of 10 to 200 angstroms.

[0089] In some optional embodiments, the lower cladding layer 101, the lower waveguide layer 102, the electron blocking layer 105, and the upper cladding layer 106 are any one or any combination of 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, Ga2O3, BN, and diamond.

[0090] In some optional embodiments, the substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, graphene, sapphire / SiN x , Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0091] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A gallium nitride-based semiconductor laser chip, comprising a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper cladding layer arranged in sequence from bottom to top, characterized in that: The upper waveguide layer has a dielectric constant distribution characteristic and a thermal conductivity distribution characteristic; The descending angle of the peak position of the dielectric constant of the upper waveguide layer toward the upper cladding layer is α, and the rising angle of the valley position of the dielectric constant of the upper waveguide layer toward the active layer is β, wherein: 10°≤α≤β≤90°; The rising angle of the valley position of the thermal conductivity of the upper waveguide layer toward the upper cladding layer is γ, and the descending angle of the peak position of the thermal conductivity of the upper waveguide layer toward the active layer is θ, wherein: 25°≤γ≤θ≤90°.

2. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The descending angle of the peak position of the dielectric constant of the upper waveguide layer toward the upper cladding layer, the rising angle of the valley position of the dielectric constant of the upper waveguide layer toward the active layer, the rising angle of the valley position of the thermal conductivity of the upper waveguide layer toward the upper cladding layer, and the descending angle of the peak position of the thermal conductivity of the upper waveguide layer toward the active layer have the following relationship: 10°≤α≤β≤γ≤θ≤90°.

3. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The upper waveguide layer also has polarization optical phonon energy distribution characteristics, longitudinal phonon velocity distribution characteristics, peak electron drift velocity distribution characteristics and bulk elastic modulus distribution characteristics; The rising angle of the valley position of the polarized optical phonon energy of the upper waveguide layer toward the upper cladding layer is δ; The rising angle of the valley position of the longitudinal phonon velocity of the upper waveguide layer toward the upper cladding layer is σ; The peak position of the peak electron drift rate of the upper waveguide layer decreases at an angle toward the upper cladding layer. The rising angle of the valley position of the bulk elastic modulus of the upper waveguide layer toward the upper cladding layer is ρ; in:

4. The gallium nitride-based semiconductor laser chip according to claim 3, characterized in that: The peak position of the polarized optical phonon energy of the upper waveguide layer decreases at an angle ψ toward the active layer; The decreasing angle of the peak position of the longitudinal phonon velocity of the upper waveguide layer toward the active layer is μ; The rising angle of the valley position of the peak electron drift velocity of the upper waveguide layer toward the active layer is υ; The peak position of the bulk elastic modulus of the upper waveguide layer decreases at an angle ω toward the active layer; Among them: 10°≤ψ≤μ≤υ≤ω≤90°.

5. The gallium nitride-based semiconductor laser chip according to claim 4, characterized in that: The polarized optical phonon energy, longitudinal phonon velocity, and the rising angle of the valley position of the bulk modulus of the upper waveguide layer toward the upper cladding layer, the falling angle of the peak position of the peak electron drift velocity of the upper waveguide layer toward the upper cladding layer, the polarized optical phonon energy, longitudinal phonon velocity, and the peak position of the bulk modulus of the upper waveguide layer toward the active layer, and the rising angle of the valley position of the peak electron drift velocity of the upper waveguide layer toward the active layer have the following relationship:

6. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The upper waveguide layer is any one or any combination of InGaN, GaN, InN, AlInGaN, and AlInN, and has a thickness of 10 nm to 1000 nm.

7. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The dielectric constant of the upper waveguide layer has the function y1=A+Blog a ((m+x) / (mx)) The fourth quadrant curve distribution, and 0<a<1, m>0; The thermal conductivity of the upper waveguide layer has the function y2=C+Dlog b ((n+x) / (nx)) The second quadrant curve distribution, and b>1, n>0; Wherein, x is the depth of the upper waveguide layer toward the electron blocking layer, C≤A.

8. The gallium nitride-based semiconductor laser chip according to claim 3, characterized in that: The polari-optical phonon energy of the upper waveguide layer has a function y3=E+Farccscx curve distribution; The longitudinal phonon velocity of the upper waveguide layer has a first quadrant curve distribution of function y4=G+Hx / lnx; The bulk elastic modulus of the upper waveguide layer has the function y5=J+Ksinx / x 2 The first quadrant curve distribution; The peak electron drift velocity of the upper waveguide layer has the function y6=L+M(c x +1) / (c x -1) The first quadrant curve distribution, and 0<c<1; Wherein, x is the depth of the upper waveguide layer toward the electron blocking layer, E≤J≤G≤L.

9. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The active layer is a periodic structure composed of a well layer and a barrier layer; The well layer of the active layer is any one or any combination of 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, Ga2O3, BN, and diamond, and has a thickness of 10 angstroms to 100 angstroms; The barrier layer of the active layer is any one or any combination of 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, Ga2O3, BN, and diamond, and has a thickness of 10 to 200 angstroms.

10. The gallium nitride-based semiconductor laser chip according to claim 1, characterized in that: The lower cladding layer, the lower waveguide layer, the electron blocking layer, and the upper cladding layer are any one or any combination of 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, Ga2O3, BN, and diamond; The substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, graphene, sapphire / SiN x , Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

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