Gallium nitride-based compound semiconductor laser chip

Abstract

The gallium nitride-based compound semiconductor laser chip comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer which are sequentially arranged from bottom to top, a hyperbolic polariton layer is arranged between the lower limiting layer and the lower waveguide layer, and breakdown field intensity distribution in the hyperbolic polariton layer is designed. And a breakdown field strength relationship among the lower limiting layer, the lower waveguide layer and the hyperbolic polariton layer. The performance of the semiconductor laser chip can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor optoelectronic devices, and in particular to a gallium nitride-based compound 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:

[0009] 1) The large internal lattice mismatch and strain cause strong polarization effect, and the QCSE quantum confined Stark effect strongly limits the improvement of the laser lasing gain;

[0010] 2) The optical waveguide absorption loss is high. Intrinsic carbon impurities in p-type semiconductors will compensate for acceptors and destroy p-type. The ionization rate of p-type doping is low, and a large amount of unionized Mg acceptor impurities will cause internal optical losses to increase.

[0011] 3) Increasing the thickness of the lower confinement layer can reduce the refractive index of the confinement layer, but increasing the thickness of the lower confinement layer will limit the range of component regulation, and easily cause problems such as cracking, bending and quality degradation; at the same time, the light field mode leaks to the substrate to form a standing wave, which will lead to low substrate mode suppression efficiency and poor far-field image FFP quality;

[0012] 4) The activation energy of the Mg acceptor in the p-type semiconductor is large, the ionization efficiency is low, the hole concentration is much lower than the electron concentration, and the hole mobility is much lower than the electron mobility, resulting in serious asymmetric mismatch between electrons and holes in the quantum well, electron leakage and carrier delocalization, more difficult hole transport in the quantum well, uneven carrier injection, uneven gain, broadening of the laser gain spectrum, and decreased peak gain. Summary of the invention

[0013] In order to solve one of the above technical problems, the present invention provides a gallium nitride-based compound semiconductor laser chip.

[0014] An embodiment of the present invention provides a gallium nitride-based compound semiconductor laser chip, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer arranged in sequence from bottom to top, a hyperbolic polariton layer is arranged between the lower confinement layer and the lower waveguide layer, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have a breakdown field strength distribution characteristic, and the breakdown field strength of the lower waveguide layer is ≥ the breakdown field strength of the hyperbolic polariton layer ≥ the breakdown field strength of the lower confinement layer, and the breakdown field strength of the hyperbolic polariton layer has a function y1=A+B*sinx / x 2 The third quadrant curve distribution, x is the depth of the hyperbolic polariton layer toward the lower waveguide layer.

[0015] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have thermal conductivity distribution characteristics, and the thermal conductivity of the lower waveguide layer is ≤ the thermal conductivity of the hyperbolic polariton layer ≤ the thermal conductivity of the lower confinement layer, and the thermal conductivity of the hyperbolic polariton layer has a function y2=C+D*e x / x 2 Second quadrant curve distribution.

[0016] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have a refractive index distribution characteristic, and the refractive index of the lower waveguide layer is ≥ the refractive index of the hyperbolic polariton layer ≥ the refractive index of the lower confinement layer, and the refractive index of the hyperbolic polariton layer has a function y3=E+F*e x / xThird quadrant curve distribution.

[0017] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have lattice constant distribution characteristics, and the lattice constant of the lower waveguide layer is ≥ the lattice constant of the hyperbolic polariton layer ≥ the lattice constant of the lower confinement layer, and the lattice constant of the hyperbolic polariton layer has a function y4=G+H*(e x +e -x ) / (e x -e -x ) curve distribution, and C≤G≤E≤A.

[0018] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / Al element ratio distribution characteristic, and the In / Al element ratio of the lower waveguide layer is ≥ the In / Al element ratio of the hyperbolic polariton layer ≥ the In / Al element ratio of the lower confinement layer, and the In / Al element ratio of the hyperbolic polariton layer has a function y5=J+K*sinx / x 2 The third quadrant curve distribution.

[0019] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / H element ratio distribution characteristic, and the In / H element ratio of the lower waveguide layer is ≥ the In / H element ratio of the hyperbolic polariton layer ≥ the In / H element ratio of the lower confinement layer, and the In / Al element ratio of the hyperbolic polariton layer has a function y6=L+M*e x / xThird quadrant curve distribution.

[0020] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / O element ratio distribution characteristic, and the In / O element ratio of the lower waveguide layer is ≥ the In / O element ratio of the hyperbolic polariton layer ≥ the In / O element ratio of the lower confinement layer, and the In / O element ratio of the hyperbolic polariton layer has a function y7=N+P*(e x +e -x ) / (e x -e -x ) curve distribution.

[0021] Preferably, the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / C element ratio distribution characteristic, and the In / C element ratio of the lower waveguide layer is ≥ the In / C element ratio of the hyperbolic polariton layer ≥ the In / C element ratio of the lower confinement layer, and the In / C element ratio of the hyperbolic polariton layer has a function y8=Q+R*(e x +e -x ) / (e x -e -x ) curve distribution, and L≤N≤Q≤J.

[0022] Preferably, the hyperbolic polariton layer is any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN.

[0023] Preferably, the active layer 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 any one or any 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 combination, with a thickness of 10 angstroms to 120 angstroms, and the barrier 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, and BN, with a thickness of 10 angstroms to 200 angstroms.

[0024] Preferably, the lower limiting layer, the lower waveguide layer, the upper waveguide layer, and the upper limiting 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, and BN.

[0025] Preferably, the substrate comprises sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0026] The beneficial effects of the present invention are as follows: the present invention arranges a hyperbolic polariton layer between the lower confinement layer and the lower waveguide layer of a gallium nitride-based compound semiconductor laser chip, designs the breakdown field intensity distribution in the hyperbolic polariton layer, and designs the relationship between the breakdown field intensity among the lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer. The hyperbolic polariton layer has effective Hawking radiation, which enables polaritons to propagate in a closed loop in the nanocavity, compensates for dielectric loss, regulates the hyperbolic dispersion of the two-dimensional polariton wave packet, reduces the leakage of the light field mode to the substrate, suppresses the substrate mode, improves the ripples appearing in the laser far-field image FFP, forms single-mode laser emission, and breaks the time reversal or space inversion symmetry, so that the valence band and the conduction band contact at discrete points in the wave vector space, and regulates the circularly polarized light propagating in the direction of chiral displacement to obtain different phases and attenuation, reduces the light absorption of the upper waveguide layer and the lower waveguide layer, reduces the internal optical loss, improves the aging light attenuation, and enhances the hole injection efficiency, improves the electro-lasing gain, reduces the excitation threshold of the laser element and improves the gain uniformity, enhances the limitation factor, improves the optical power and slope efficiency of the laser element, and further improves the aging light attenuation. The hyperbolic polaritons layer forms hyperbolic polaritons that are a mixture of electromagnetic modes and dipole excitations, generating non-zero topological charges at the interface, so that the propagation of lasers in topological edge states is not restricted by the laws of reflection and refraction, reducing the propagation loss of the laser, increasing the optical power of the laser and reducing aging light attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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:

[0028] Figure 1 This is a schematic structural diagram of a gallium nitride-based compound semiconductor laser chip according to an embodiment of the present invention;

[0029] Figure 2 This is a SIMS secondary ion mass spectrum of the gallium nitride-based compound semiconductor laser chip described in an embodiment of the present invention.

[0030] Reference numerals:

[0031] 100. substrate, 101. lower confinement layer, 102. lower waveguide layer, 103. active layer, 104. upper waveguide layer, 105. upper confinement layer, 106. hyperbolic polariton layer. DETAILED DESCRIPTION

[0032] 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.

[0033] like Figure 1 and Figure 2 As shown, this embodiment provides a gallium nitride-based compound semiconductor laser chip, comprising 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 arranged in sequence from bottom to top, and a hyperbolic polariton layer 106 is also arranged in the gallium nitride-based compound semiconductor laser chip.

[0034] Specifically, in this embodiment, the gallium nitride-based compound semiconductor laser chip is provided with 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 in order from bottom to top. A hyperbolic polariton layer 106 is also provided in the semiconductor laser element. The hyperbolic polariton layer 106 is provided between the lower confinement layer 101 and the lower waveguide layer 102.

[0035] In this embodiment, the lower confinement layer 101, the lower waveguide layer 102 and the hyperbolic polariton layer 106 all have breakdown field intensity distribution characteristics, and the breakdown field intensity in the lower confinement layer 101, the lower waveguide layer 102 and the hyperbolic polariton layer 106 has the following relationship:

[0036] The breakdown field strength of lower waveguide layer 102 ≥ the breakdown field strength of hyperbolic polariton layer 106 ≥ the breakdown field strength of lower confinement layer 101 .

[0037] Furthermore, this embodiment also designs the breakdown field intensity distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0038] The breakdown field strength of the hyperbolic polariton layer 106 has the function y1=A+B*sinx / x 2 The third quadrant curve distribution, wherein x is the depth of the hyperbolic polariton layer 106 toward the lower waveguide layer 102 .

[0039] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 also have thermal conductivity distribution characteristics, and the thermal conductivities of lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0040] The thermal conductivity of lower waveguide layer 102 ≤ the thermal conductivity of hyperbolic polariton layer 106 ≤ the thermal conductivity of lower confinement layer 101 .

[0041] Furthermore, this embodiment also designs the thermal conductivity distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0042] The thermal conductivity of the hyperbolic polariton layer 106 has the function y2=C+D*e x / x 2 Second quadrant curve distribution.

[0043] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 further have a refractive index coefficient distribution characteristic, and the refractive index coefficients of lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0044] The refractive index coefficient of lower waveguide layer 102 ≥ the refractive index coefficient of hyperbolic polariton layer 106 ≥ the refractive index coefficient of lower confinement layer 101 .

[0045] Furthermore, this embodiment also designs the refractive index coefficient distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0046] The refractive index coefficient of the hyperbolic polariton layer 106 has the function y3=E+F*e x / xThird quadrant curve distribution.

[0047] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 also have lattice constant distribution characteristics, and the lattice constants in lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0048] The lattice constant of lower waveguide layer 102 ≥ the lattice constant of hyperbolic polariton layer 106 ≥ the lattice constant of lower confinement layer 101 .

[0049] Furthermore, this embodiment also designs the lattice constant distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0050] The lattice constant of the hyperbolic polariton layer 106 has the function y4=G+H*(e x +e -x ) / (e x -e -x ) curve distribution, where C≤G≤E≤A.

[0051] The hyperbolic polariton layer 106 has effective Hawking radiation, which allows polaritons to propagate in a closed loop in the nanocavity, compensates for dielectric loss, regulates the hyperbolic dispersion of the two-dimensional polariton wave packet, reduces the leakage of the light field mode to the substrate, suppresses the substrate mode, improves the ripples appearing in the laser far-field image FFP, forms single-mode laser emission, and breaks the time reversal or space inversion symmetry, so that the valence band and the conduction band contact at discrete points in the wave vector space, and regulates the circularly polarized light propagating in the chiral displacement direction to obtain different phases and attenuations, reduces the light absorption of the upper waveguide layer 104 and the lower waveguide layer 102, reduces internal optical losses, improves aging light attenuation, and enhances hole injection efficiency, improves electro-lasing gain, reduces the excitation threshold of the laser element and improves gain uniformity, enhances the confinement factor, improves the optical power and slope efficiency of the laser element, and further improves aging light attenuation. The hyperbolic polariton layer 106 forms a hyperbolic polariton of a mixture of electromagnetic mode and dipole excitation, generating a non-zero topological charge at the interface, so that the propagation of the laser in the topological edge state is not restricted by the laws of reflection and refraction, reducing the propagation loss of the laser, improving the optical power of the laser and reducing the aging light attenuation.

[0052] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 also have an In / Al element ratio distribution characteristic, and the In / Al element ratios in lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0053] The In / Al element ratio of the lower waveguide layer 102 ≥ the In / Al element ratio of the hyperbolic polariton layer 106 ≥ the In / Al element ratio of the lower confinement layer 101 .

[0054] Furthermore, the present embodiment also designs the In / Al element ratio distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0055] The In / Al element ratio of the hyperbolic polariton layer 106 has the function y5=J+K*sinx / x 2 The third quadrant curve distribution.

[0056] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 also have an In / H element ratio distribution characteristic, and the In / H element ratios in lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0057] The In / H element ratio of the lower waveguide layer 102 ≥ the In / H element ratio of the hyperbolic polariton layer 106 ≥ the In / H element ratio of the lower confinement layer 101 .

[0058] Furthermore, the present embodiment also designs the In / H element ratio distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0059] The In / Al element ratio of the hyperbolic polariton layer 106 has the function y6=L+M*e x / xThird quadrant curve distribution.

[0060] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102 and the hyperbolic polariton layer 106 also have an In / O element ratio distribution characteristic, and the In / O element ratios in the lower confinement layer 101, the lower waveguide layer 102 and the hyperbolic polariton layer 106 have the following relationship:

[0061] The In / O element ratio of the lower waveguide layer 102 ≥ the In / O element ratio of the hyperbolic polariton layer 106 ≥ the In / O element ratio of the lower confinement layer 101 .

[0062] Furthermore, this embodiment also designs the In / O element ratio distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0063] The In / O ratio of the hyperbolic polariton layer 106 has a function y7=N+P*(e x +e -x ) / (e x -e -x ) curve distribution.

[0064] In some optional embodiments, lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 also have an In / C element ratio distribution characteristic, and the In / C element ratios in lower confinement layer 101, lower waveguide layer 102 and hyperbolic polariton layer 106 have the following relationship:

[0065] The In / C element ratio of the lower waveguide layer 102 ≥ the In / C element ratio of the hyperbolic polariton layer 106 ≥ the In / C element ratio of the lower confinement layer 101 .

[0066] Furthermore, this embodiment also designs the In / C element ratio distribution of the hyperbolic polariton layer 106, which is specifically shown as follows:

[0067] The In / C element ratio of the hyperbolic polariton layer 106 has a function y8=Q+R*(e x +e -x ) / (e x -e -x ) curve distribution, where L≤N≤Q≤J.

[0068] In some optional embodiments, the hyperbolic polariton layer 106 is any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN, preferably GaN / InGaN.

[0069] In some optional embodiments, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, and the number of periods is 3≥m≥1.

[0070] Specifically, the well 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, and BN, and has a thickness of 10 to 120 angstroms.

[0071] The barrier 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, and BN, with a thickness of 10 to 200 angstroms.

[0072] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102, the upper waveguide layer 104, and the upper confinement layer 105 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, and BN.

[0073] In some optional embodiments, the substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0074] The following table is a parameter comparison between a conventional semiconductor laser element and the gallium nitride-based compound semiconductor laser chip proposed in this embodiment, including beam quality factor, slope efficiency, threshold current density, optical power 1000H aging light attenuation, internal optical loss and limiting factor, showing the difference between the conventional semiconductor laser element and the gallium nitride-based compound semiconductor laser chip proposed in this embodiment:

[0075]

[0076]

[0077] It can be seen that the gallium nitride-based compound semiconductor laser chip proposed in this embodiment has improved beam quality factor, slope efficiency, optical power and limiting factor, reduced threshold current density, 1000H aging light attenuation and internal optical loss compared with traditional semiconductor laser elements, and has obvious advantages over traditional semiconductor laser elements.

[0078] 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 compound semiconductor laser chip, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer arranged in sequence from bottom to top, characterized in that: A hyperbolic polariton layer is arranged between the lower limiting layer and the lower waveguide layer, and the lower limiting layer, the lower waveguide layer and the hyperbolic polariton layer all have a breakdown field strength distribution characteristic, and the breakdown field strength of the lower waveguide layer is ≥ the breakdown field strength of the hyperbolic polariton layer ≥ the breakdown field strength of the lower limiting layer, and the breakdown field strength of the hyperbolic polariton layer has a function y1=A+B*sinx / x 2 The third quadrant curve distribution, x is the depth of the hyperbolic polariton layer toward the lower waveguide layer.

2. The gallium nitride-based compound semiconductor laser chip according to claim 1, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have thermal conductivity distribution characteristics, and the thermal conductivity of the lower waveguide layer is ≤ the thermal conductivity of the hyperbolic polariton layer ≤ the thermal conductivity of the lower confinement layer, and the thermal conductivity of the hyperbolic polariton layer has a function y2=C+D*e x / x 2 Second quadrant curve distribution.

3. The gallium nitride-based compound semiconductor laser chip according to claim 2, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have a refractive index distribution characteristic, and the refractive index of the lower waveguide layer is ≥ the refractive index of the hyperbolic polariton layer ≥ the refractive index of the lower confinement layer, and the refractive index of the hyperbolic polariton layer has a function y3=E+F*e x / xThird quadrant curve distribution.

4. The gallium nitride-based compound semiconductor laser chip according to claim 3, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have lattice constant distribution characteristics, and the lattice constant of the lower waveguide layer is ≥ the lattice constant of the hyperbolic polariton layer ≥ the lattice constant of the lower confinement layer, and the lattice constant of the hyperbolic polariton layer has a function y4=G+H*(e x +e -x ) / (e x -e -x ) curve distribution, and C≤G≤E≤A.

5. The gallium nitride-based compound semiconductor laser chip according to claim 1, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / Al element ratio distribution characteristic, and the In / Al element ratio of the lower waveguide layer is ≥ the In / Al element ratio of the hyperbolic polariton layer ≥ the In / Al element ratio of the lower confinement layer, and the In / Al element ratio of the hyperbolic polariton layer has a function y5=J+K*sinx / x 2 The third quadrant curve distribution.

6. The gallium nitride-based compound semiconductor laser chip according to claim 5, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / H element ratio distribution characteristic, and the In / H element ratio of the lower waveguide layer is ≥ the In / H element ratio of the hyperbolic polariton layer ≥ the In / H element ratio of the lower confinement layer, and the In / Al element ratio of the hyperbolic polariton layer has a function y6=L+M*e x / xThird quadrant curve distribution.

7. The gallium nitride-based compound semiconductor laser chip according to claim 6, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / O element ratio distribution characteristic, and the In / O element ratio of the lower waveguide layer is ≥ the In / O element ratio of the hyperbolic polariton layer ≥ the In / O element ratio of the lower confinement layer, and the In / O element ratio of the hyperbolic polariton layer has a function y7=N+P*(e x +e -x ) / (e x -e -x ) curve distribution.

8. The gallium nitride-based compound semiconductor laser chip according to claim 7, characterized in that: The lower confinement layer, the lower waveguide layer and the hyperbolic polariton layer all have an In / C element ratio distribution characteristic, and the In / C element ratio of the lower waveguide layer is ≥ the In / C element ratio of the hyperbolic polariton layer ≥ the In / C element ratio of the lower confinement layer, and the In / C element ratio of the hyperbolic polariton layer has a function y8=Q+R*(e x +e -x ) / (e x -e -x ) curve distribution, and L≤N≤Q≤J.

9. The gallium nitride-based compound semiconductor laser chip according to claim 1, characterized in that: The hyperbolic polariton layer is any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN.

10. The gallium nitride-based compound 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 number of periods is 3≥m≥1, and the well 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, and BN , with a thickness of 10 angstroms to 120 angstroms, and the barrier 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, and BN, with a thickness of 10 angstroms to 200 angstroms; The lower confinement layer, the lower waveguide layer, the upper waveguide layer, and the upper confinement 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, and BN; The substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

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