Semiconductor laser element

Abstract

The invention discloses a semiconductor laser element which sequentially comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer from bottom to top, and a dark exciton resonance layer is arranged between the active layer and the lower waveguide layer. The dark exciton resonance layer comprises a first dark exciton resonance layer, a second dark exciton resonance layer and a third dark exciton resonance layer. The effective mass distribution and refractive index distribution of specific electrons of the dark exciton resonance layer enhance the strong coupling effect of dark excitons and photons, reduce the effective quality of exciton polaritons, improve the group velocity, enhance the dipole resonance intensity and the nonlinear effect of the exciton polaritons, enhance the coherence of the dark exciton polaritons, and improve the quantum efficiency. The laser modulus is reduced, the photon degeneracy is improved, the output laser coherence is improved, and the beam quality factor is improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a semiconductor laser element. 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 significant 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 is up to 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;

[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 optical waveguide has high absorption loss. Intrinsic carbon impurities in p-type semiconductors will compensate for acceptors and destroy p-type. The ionization rate of p-type doping is low. A large amount of unionized Mg acceptor impurities will cause internal optical losses to increase. In addition, the refractive index dispersion of the laser and the fluctuation of high-concentration carrier concentration affect the refractive index of the active layer. The limiting factor decreases with increasing wavelength, resulting in a decrease in the mode gain of the laser.

[0010] 2. The shape of laser light waves can be divided into transverse mode and longitudinal mode. The transverse mode intensity distribution in the cross section perpendicular to the optical axis is determined by the waveguide structure of the semiconductor laser. If the transverse mode is complex and unstable, the coherence of the output light will be poor. The longitudinal mode is a standing wave distribution in the propagation direction of the resonant cavity. If many longitudinal modes are emitted at the same time or there are inter-mode changes, high temporal coherence cannot be obtained. Summary of the invention

[0011] The present invention provides a semiconductor laser element. The specific electron effective mass distribution and refractive index distribution of the dark exciton resonance layer enhance the strong coupling effect between dark excitons and photons, reduce the effective mass of exciton polaritons and increase the group velocity, enhance the dipole resonance intensity and the nonlinear effect of exciton polaritons, enhance the coherence of dark exciton polaritons, reduce the laser mode number, increase the photon degeneracy, enhance the output laser coherence, and enhance the beam quality factor.

[0012] A semiconductor laser element provided by the present invention 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 a dark exciton resonance layer is provided between the active layer and the lower waveguide layer.

[0013] The dark exciton resonance layer is GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InG aAsN, 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;

[0014] The dark exciton resonance layer includes a first dark exciton resonance layer, a second dark exciton resonance layer and a third dark exciton resonance layer.

[0015] Preferably, the spontaneous polarization coefficient distribution of the first dark exciton resonance layer has a first quadrant curve distribution of the function y=A+B*x / lnx; the spontaneous polarization coefficient distribution of the second dark exciton resonance layer has a linear function distribution; the spontaneous polarization coefficient distribution of the third dark exciton resonance layer has a first quadrant curve distribution of y=C+D*xe x Curved distribution.

[0016] Preferably, the spontaneous polarization coefficient of the first dark exciton resonance layer is a, the spontaneous polarization coefficient of the second dark exciton resonance layer is b, and the spontaneous polarization coefficient of the third dark exciton resonance layer is c, wherein: -0.5≤a≤b≤c≤-0.01.

[0017] Preferably, the electron affinity energy distribution of the first dark exciton resonance layer has a function y=E+F*lnx / x curve distribution; the electron affinity energy distribution of the second dark exciton resonance layer has a linear function distribution; the electron affinity energy distribution of the third dark exciton resonance layer has a second four-quadrant curve distribution of y=G+H*cosx / x.

[0018] Preferably, the electron affinity of the first dark exciton resonance layer is d, the electron affinity of the second dark exciton resonance layer is e, and the electron affinity of the third dark exciton resonance layer is f, wherein: 0.1≤e≤d≤f≤10.

[0019] Preferably, the electron effective mass distribution of the first dark exciton resonance layer has a function y=J+K*lnx / e x curve distribution; the electron effective mass distribution of the second dark exciton resonance layer has a linear function distribution; the electron effective mass distribution of the third dark exciton resonance layer has y=L+M*e x / x 2 Second quadrant curve distribution.

[0020] Preferably, the electron effective mass of the first dark exciton resonance layer is g, the electron effective mass of the second dark exciton resonance layer is h, and the electron effective mass of the third dark exciton resonance layer is i, wherein: 0.01≤i≤h≤g≤5.

[0021] Preferably, the refractive index coefficient distribution of the first dark exciton resonance layer has a function y=N+P*sinx / x 2 The first quadrant curve distribution; the refractive index coefficient distribution of the second dark exciton resonance layer has a linear function distribution; the refractive index coefficient distribution of the third dark exciton resonance layer has y=Q+R*x 2 e x Curved distribution.

[0022] Preferably, the refractive index coefficient distribution of the first dark exciton resonance layer is j, the refractive index coefficient distribution of the second dark exciton resonance layer is k, and the refractive index coefficient distribution of the third dark exciton resonance layer is l, wherein: 1≤j≤k≤l≤10.

[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 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, any one or any combination thereof, with a thickness of 10 to 100 angstroms, and a barrier layer 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, Ga 2 O 3 , BN, diamond or any combination thereof, with a thickness of 10 to 150 angstroms.

[0024] Preferably, the lower limiting layer, the lower waveguide layer, the upper waveguide layer, and the upper limiting layer 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 , any one or any combination of BN.

[0025] Preferably, the substrate comprises sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO 2Composite substrates, Mo, TiW, CuW, Cu, sapphire / AlN composite substrates, diamond, sapphire / SiN x , Sapphire / SiO 2 / SiN x Composite substrate, magnesium aluminum spinel MgAl 2 O 4 、MgO、ZnO、ZrB 2 、LiAlO 2 and LiGaO 2 Any type of composite substrate.

[0026] Compared with the prior art, the semiconductor laser element provided by the embodiment of the present invention has the following beneficial effects:

[0027] 1. The dark exciton resonance layer excites the spontaneous polarization coefficient distribution of the active layer to induce the dark excitons to generate out-of-plane transition dipoles, enhance the dark exciton resonance to enhance laser lasing, and improve the photoelectric conversion efficiency coupled with the dark excitons, thereby improving the luminous power and slope efficiency of the laser.

[0028] 2. The specific electron affinity energy distribution of the dark exciton resonance layer induces anti-Stokes laser radiation, balances dispersion and self-phase modulation, balances laser gain and uniform loss, reduces group velocity dispersion and high-order dispersion of the waveguide layer, reduces optical waveguide absorption loss and internal optical loss, and improves laser power and slope efficiency.

[0029] 3. The specific electron effective mass distribution and refractive index distribution of the dark exciton resonance layer enhance the strong coupling effect between dark excitons and photons, reduce the effective mass of exciton polaritons and increase the group velocity, enhance the dipole resonance intensity and the nonlinear effect of exciton polaritons, enhance the coherence of dark exciton polaritons, reduce the laser mode number, increase the photon degeneracy, enhance the output laser coherence, and improve the beam quality factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a semiconductor laser element provided by the present invention.

[0031] Figure 2 A SIMS secondary ion mass spectrum of a semiconductor laser element provided by the present invention.

[0032] In the figure, markings are as follows: 100: substrate; 101: lower confinement layer; 102: lower waveguide layer; 103: active layer; 104: upper waveguide layer, 105: upper confinement layer, 106: dark exciton resonance layer, 106a: first dark exciton resonance layer, 106b: second dark exciton resonance layer, 106c: third dark exciton resonance layer. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In order to solve the above problems, a semiconductor laser element provided in an embodiment of the present application will be introduced and explained in detail through the following specific embodiments.

[0035] Reference Figure 1-2 A semiconductor laser element provided by the present invention comprises, 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. A dark exciton resonance layer 106 is provided between the active layer 103 and the lower waveguide layer 102. The dark exciton resonance layer 106 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; the dark exciton resonance layer 106 includes a first dark exciton resonance layer 106a, a second dark exciton resonance layer 106b and a third dark exciton resonance layer 106c.

[0036] The spontaneous polarization coefficient distribution of the first dark exciton resonance layer 106a has a first quadrant curve distribution of the function y=A+B*x / lnx; the spontaneous polarization coefficient distribution of the second dark exciton resonance layer 106b has a linear function distribution; the spontaneous polarization coefficient distribution of the third dark exciton resonance layer 106c has a first quadrant curve distribution of y=A+B*x / lnx; x Curve distribution; the spontaneous polarization coefficient of the first dark exciton resonance layer 106a is a, the spontaneous polarization coefficient of the second dark exciton resonance layer 106b is b, and the spontaneous polarization coefficient of the third dark exciton resonance layer 106c is c, wherein: -0.5≤a≤b≤c≤-0.01.

[0037] The electron affinity energy distribution of the first dark exciton resonance layer 106a has a function y=E+F*lnx / x curve distribution; the electron affinity energy distribution of the second dark exciton resonance layer 106b has a linear function distribution; the electron affinity energy distribution of the third dark exciton resonance layer 106c has a second four-quadrant curve distribution of y=G+H*cosx / x; the electron affinity energy of the first dark exciton resonance layer 106a is d, the electron affinity energy of the second dark exciton resonance layer 106b is e, and the electron affinity energy of the third dark exciton resonance layer 106c is f, wherein: 0.1≤e≤d≤f≤10.

[0038] The electron effective mass distribution of the first dark exciton resonance layer 106a has a function y=J+K*lnx / e x Curve distribution; the electron effective mass distribution of the second dark exciton resonance layer 106b has a linear function distribution; the electron effective mass distribution of the third dark exciton resonance layer 106c has y=L+M*e x / x 2 The second quadrant curve distribution: The electron effective mass of the first dark exciton resonance layer 106a is g, the electron effective mass of the second dark exciton resonance layer 106b is h, and the electron effective mass of the third dark exciton resonance layer 106c is i, wherein: 0.01≤i≤h≤g≤5.

[0039] The refractive index coefficient distribution of the first dark exciton resonance layer 106a has a function y=N+P*sinx / x 2 The first quadrant curve distribution; the refractive index coefficient distribution of the second dark exciton resonance layer 106b has a linear function distribution; the refractive index coefficient distribution of the third dark exciton resonance layer 106c has y=Q+R*x 2 e x The refractive index coefficient of the first dark exciton resonance layer 106a is distributed as j, the refractive index coefficient of the second dark exciton resonance layer 106b is distributed as k, and the refractive index coefficient of the third dark exciton resonance layer 106c is distributed as l, wherein: 1≤j≤k≤l≤10.

[0040] The specific data are shown in the following table, which compares the data of the traditional laser and the laser of the present invention.

[0041] Blue Laser Project Conventional laser Laser of the present invention Range of change <![CDATA[Beam quality factor M 2 > 3.7 1.19 211％ Slope efficiency (W / A) 0.8 1.58 98％ <![CDATA[Threshold current density (kA / cm 2 )]]> 2.4 0.67 -72％ Optical power(W) 4.1 8.6 110％ <![CDATA[Internal optical loss (cm -1 )]]> 17.2 11.3 -34％

[0042] In the present invention, 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, any one or any combination thereof, with a thickness of 10 to 100 angstroms, and a barrier layer 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, Ga 2 O 3 , BN, diamond or any combination thereof, with a thickness of 10 to 150 angstroms.

[0043] In the present invention, the lower confinement layer 101, the lower waveguide layer 102, the upper waveguide layer 104, 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 , any one or any combination of BN.

[0044] In the present invention, the substrate 100 includes 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 / SiO 2 / SiN xComposite substrate, magnesium aluminum spinel MgAl 2 O 4 、MgO、ZnO、ZrB 2 、LiAlO 2 and LiGaO 2 Any type of composite substrate.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A semiconductor laser element, comprising, from bottom to top, a substrate (100), a lower confinement layer (101), a lower waveguide layer (102), an active layer (103), an upper waveguide layer (104), and an upper confinement layer (105), characterized in that: A dark exciton resonance layer (106) is provided between the lower confinement layer (101) and the lower waveguide layer (102). The dark exciton resonance layer (106) 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; The dark exciton resonance layer (106) comprises a first dark exciton resonance layer (106a), a second dark exciton resonance layer (106b) and a third dark exciton resonance layer (106c).

2. A semiconductor laser element according to claim 1, characterized in that: The spontaneous polarization coefficient distribution of the first dark exciton resonance layer (106a) has a first quadrant curve distribution of the function y=A+B*x / lnx; the spontaneous polarization coefficient distribution of the second dark exciton resonance layer (106b) has a linear function distribution; the spontaneous polarization coefficient distribution of the third dark exciton resonance layer (106c) has a first quadrant curve distribution of y=C+D*x / lnx; x Curved distribution.

3. A semiconductor laser element according to claim 2, characterized in that: The spontaneous polarization coefficient of the first dark exciton resonance layer (106a) is a, the spontaneous polarization coefficient of the second dark exciton resonance layer (106b) is b, and the spontaneous polarization coefficient of the third dark exciton resonance layer (106c) is c, wherein: -0.5≤a≤b≤c≤-0.

01.

4. A semiconductor laser element according to claim 1, characterized in that: The electron affinity energy distribution of the first dark exciton resonance layer (106a) has a function y=E+F*lnx / x curve distribution; the electron affinity energy distribution of the second dark exciton resonance layer (106b) has a linear function distribution; and the electron affinity energy distribution of the third dark exciton resonance layer (106c) has a second four-quadrant curve distribution of y=G+H*cosx / x.

5. A semiconductor laser element according to claim 4, characterized in that: The electron affinity of the first dark exciton resonance layer (106a) is d, the electron affinity of the second dark exciton resonance layer (106b) is e, and the electron affinity of the third dark exciton resonance layer (106c) is f, wherein: 0.1≤e≤d≤f≤10.

6. A semiconductor laser element according to claim 1, characterized in that: The electron effective mass distribution of the first dark exciton resonance layer (106a) has a function y=J+K*lnx / e x curve distribution; the electron effective mass distribution of the second dark exciton resonance layer (106b) has a linear function distribution; the electron effective mass distribution of the third dark exciton resonance layer (106c) has y=L+M*e x / x 2 Second quadrant curve distribution.

7. A semiconductor laser element according to claim 6, characterized in that: The electron effective mass of the first dark exciton resonance layer (106a) is g, the electron effective mass of the second dark exciton resonance layer (106b) is h, and the electron effective mass of the third dark exciton resonance layer (106c) is i, wherein: 0.01≤i≤h≤g≤5.

8. The semiconductor laser element according to claim 1, characterized in that: The refractive index coefficient distribution of the first dark exciton resonance layer (106a) has a function y=N+P*sinx / x 2 The first quadrant curve distribution; the refractive index coefficient distribution of the second dark exciton resonance layer (106b) has a linear function distribution; the refractive index coefficient distribution of the third dark exciton resonance layer (106c) has y=Q+R*x 2 e x Curved distribution.

9. A semiconductor laser element according to claim 8, characterized in that: The refractive index coefficient distribution of the first dark exciton resonance layer (106a) is j, the refractive index coefficient distribution of the second dark exciton resonance layer (106b) is k, and the refractive index coefficient distribution of the third dark exciton resonance layer (106c) is l, wherein: 1≤j≤k≤l≤10.

10. The semiconductor laser element according to claim 1, characterized in that: 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 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 to 100 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, BN, and diamond, with a thickness of 10 to 150 angstroms.

11. The semiconductor laser element according to claim 1, characterized in that: 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.

12. The semiconductor laser element according to claim 1, characterized in that: 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, 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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