A semiconductor laser

Abstract

The application discloses a semiconductor laser, comprising: a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper limiting layer arranged in sequence from bottom to top; the active layer comprises a well layer and a barrier layer; the lattice constant of the well layer is greater than or equal to the lattice constant of the barrier layer; the thermal expansion coefficient of the well layer is less than or equal to the thermal expansion coefficient of the barrier layer; and the elastic coefficient of the well layer is less than or equal to the elastic coefficient of the barrier layer. By designing the lattice constant of the well layer to be greater than or equal to the lattice constant of the barrier layer, the thermal expansion coefficient of the well layer to be less than or equal to the thermal expansion coefficient of the barrier layer and the elastic coefficient of the well layer to be less than or equal to the elastic coefficient of the barrier layer, the carrier capture effect, the deep level defect and the insulating interface of the depletion region of the active layer of the semiconductor laser can be effectively controlled, the symmetry breaking of the laser principle equilibrium state phase transition can be inhibited, and thus the sudden change phenomenon of the laser at the threshold can be effectively solved, and problems such as the conductance up-jump, the capacitance down-dip and the junction voltage up-jump can be eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor optoelectronic devices, and in particular to a semiconductor laser. BACKGROUND

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

[0003] The existing semiconductor laser deviates from the symmetry breaking corresponding to the equilibrium phase transition, resulting in discontinuity or mutation phenomenon at the threshold, such as conductance jump, capacitance sinking, junction voltage jump, series resistance sinking, and ideal factor jump. SUMMARY

[0004] The present application provides a semiconductor laser to solve the technical problem that the existing semiconductor laser deviates from the symmetry breaking corresponding to the equilibrium phase transition, resulting in discontinuity or mutation phenomenon at the threshold.

[0005] One embodiment of the present application provides a semiconductor laser, comprising:

[0006] a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper confinement layer are sequentially arranged from bottom to top;

[0007] The active layer comprises a well layer and a barrier layer;

[0008] The lattice constant of the well layer is greater than or equal to the lattice constant of the barrier layer;

[0009] The thermal expansion coefficient of the well layer is less than or equal to the thermal expansion coefficient of the barrier layer;

[0010] The elastic coefficient of the well layer is less than or equal to the elastic coefficient of the barrier layer.

[0011] Further, the lattice constant, thermal expansion coefficient and elastic coefficient of the active layer all present a U-shaped distribution.

[0012] Further, the period number m of the active layer satisfies 1≤m≤3.

[0013] Further, the well layer of the active layer comprises at least one of InGaN, InN, GaN, AlInGaN, AlInN and AlGaN, and the well layer of the active layer has a thickness of 10-200 angstrom meters and a light emitting wavelength of 200-500 nm.

[0014] The barrier layer of the active layer comprises at least one of GaN, AlInGaN, AlInN, AlGaN and AlN, and the barrier layer of the active layer has a thickness of 5-500 angstrom meters.

[0015] Further, the In / C element ratio of the active layer is in an inverted U-shaped distribution.

[0016] Further, the lower waveguide layer is any one or any combination of InGaN, InN, GaN, AlInGaN, AlN, AlGaN and AlInN, the thickness of the lower waveguide layer is 10-5000 angstrom meters; the upper waveguide layer is any one or any combination of InGaN, InN, GaN, AlInGaN, AlInN, AlGaN, the thickness of the upper waveguide layer is 20-6000 angstrom meters; the upper confinement layer is any one or any combination of GaN, AlInGaN, AlN, AlInN and AlGaN, the thickness of the upper confinement layer is 20-50000 angstrom meters; the lower confinement layer is any one or any combination of GaN, AlInGaN, AlN, AlInN and AlGaN, the thickness of the lower confinement layer is 50-90000 angstrom meters.

[0017] Further, the active layer is a periodic structure composed of well layers and barrier layers, the period of the periodic structure is s: 1≤s≤10; the well layer of the active layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, the thickness is t: 5≤t≤100 angstrom meters, and the light emitting wavelength is 500-1600 nm; the barrier layer of the active layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, the thickness is u: 10≤u≤200 angstrom meters.

[0018] Further, the lower waveguide layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of v: 10≤v≤9000 angstroms; the upper waveguide layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of w: 10≤w≤9000 angstroms; the lower confinement layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of r: 10≤r≤90000 angstroms; the upper confinement layer and the electron blocking layer are any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of g: 10≤g≤80000 angstroms.

[0019] Further, the substrate comprises any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiNx, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0020] In the embodiment of the present application, by designing the lattice constant of the well layer to be greater than or equal to the lattice constant of the barrier layer, the thermal expansion coefficient of the well layer to be less than or equal to the thermal expansion coefficient of the barrier layer, and the elastic coefficient of the well layer to be less than or equal to the elastic coefficient of the barrier layer, the carrier capture effect, deep level defects and insulating interface of the depletion region of the active layer of the semiconductor laser can be effectively controlled, so that the symmetry breaking of the phase transition of the laser principle balance state can be inhibited, and then the sudden change phenomenon of the laser at the threshold can be effectively solved, and the problems such as the conductance jump, the capacitance deep drop and the junction voltage jump can be eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structure schematic diagram of a semiconductor laser provided by the embodiment of the present application;

[0022] Figure 2 is a SIMS secondary ion mass spectrum diagram of a semiconductor laser provided by the embodiment of the present application;

[0023] Figure 3 is another SIMS secondary ion mass spectrum of the semiconductor laser provided by the embodiment of the present application;

[0024] Figure 4 is a TEM lens electron microscope image of the lower confinement layer of the semiconductor laser provided by the embodiment of the present application;

[0025] Figure 5 is a TEM lens electron microscope image of the active layer of the semiconductor laser provided by the embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] In the description of the present application, it should be understood that the terms “first”, “second” are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of “a plurality of” is two or more.

[0028] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms “mounting”, “connection”, “connection” should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] Please refer to Figure 1 , one embodiment of the present application provides a semiconductor laser, comprising:

[0030] The substrate 100, the lower confinement layer 101, the lower waveguide layer 102, the active layer 103, the upper waveguide layer 104, the electron blocking layer 105 and the upper confinement layer 106 are sequentially arranged from bottom to top;

[0031] The active layer 103 comprises a well layer and a barrier layer;

[0032] The lattice constant of the well layer is greater than or equal to the lattice constant of the barrier layer;

[0033] The coefficient of thermal expansion of the well layer is less than or equal to the coefficient of thermal expansion of the barrier layer.

[0034] The elastic coefficient of the well layer is less than or equal to the elastic coefficient of the barrier layer.

[0035] In the embodiment of the present application, by designing the lattice constant of the well layer to be greater than or equal to the lattice constant of the barrier layer, the coefficient of thermal expansion of the well layer to be less than or equal to the coefficient of thermal expansion of the barrier layer, and the elastic coefficient of the well layer to be less than or equal to the elastic coefficient of the barrier layer, the carrier trapping effect, deep level defects and insulating interface of the depletion region of the active layer 103 of the semiconductor laser can be effectively controlled, so that the symmetry breaking of the principle equilibrium state phase transition of the laser can be inhibited, and the sudden change phenomenon of the laser at the threshold can be effectively solved, and the problems such as the upward jump of the conductance, the downward deep of the capacitance and the upward jump of the junction voltage can be eliminated.

[0036] In one embodiment, the lattice constant, the coefficient of thermal expansion and the elastic coefficient of the active layer 103 are in U-shaped distribution.

[0037] In the embodiment of the present application, by designing the lattice constant, the coefficient of thermal expansion and the elastic coefficient of the active layer 103 to be in U-shaped distribution, the insulating interface of the laser can be effectively controlled.

[0038] In one embodiment, the number m of periods of the active layer 103 satisfies 1≤m≤3.

[0039] In the embodiment of the present application, the active layer 103 can be composed of a quantum well with a periodic structure of the well layer and the barrier layer. Since the current density of the semiconductor laser is several tens of times or even several hundreds of times of that of the LED, too many quantum wells will cause heat accumulation, resulting in burning of the device. In addition, the semiconductor laser requires that the quality and interface of the active layer 103 be very good, so that the wavelength half-width of the laser emission is narrow, forming a single-mode emission. Too many quantum wells will cause the In component to fluctuate, the half-width to become large, and the laser to produce multiple modes. Therefore, in the embodiment of the present application, the quantum well composed of the well layer and the barrier layer of the active layer 103 has a period of not more than 3, so as to avoid heat accumulation of the quantum well and multiple modes of the laser.

[0040] In one embodiment, the well layer of the active layer 103 includes at least one of InGaN, InN, GaN, AlInGaN, AlInN and AlGaN, and the thickness of the well layer of the active layer 103 is 10-200 angstroms, and the light emitting wavelength is 200-500 nm.

[0041] The barrier layer of the active layer 103 includes at least one of GaN, AlInGaN, AlInN, AlGaN and AlN, and the thickness of the barrier layer of the active layer 103 is 5-500 angstroms.

[0042] In an embodiment, the In / C element ratio of the active layer 103 is inversely U-shaped.

[0043] The lattice constant, thermal expansion coefficient and elastic coefficient of the active layer 103 of the embodiment of the present application are U-shaped, and in combination with the inversely U-shaped distribution of the In / C element ratio of the active layer 103, deep level defects can be effectively inhibited, the symmetry breaking of the laser far from the equilibrium phase transition can be inhibited, and thus the sudden change of the laser at the threshold can be effectively solved, and problems such as the conductance jump, the capacitance dip and the junction voltage jump can be eliminated.

[0044] In an embodiment, the lower waveguide layer 102 is any one or any combination of InGaN, InN, GaN, AlInGaN, AlN, AlGaN and AlInN, the thickness of the lower waveguide layer 102 is 10-5000 angstroms, the upper waveguide layer 104 is any one or any combination of InGaN, InN, GaN, AlInGaN, AlInN, AlGaN, the thickness of the upper waveguide layer 104 is 20-6000 angstroms, the upper confinement layer 106 is any one or any combination of GaN, AlInGaN, AlN, AlInN and AlGaN, the thickness of the upper confinement layer 106 is 20-50000 angstroms, and the lower confinement layer 101 is any one or any combination of GaN, AlInGaN, AlN, AlInN and AlGaN, the thickness of the lower confinement layer 101 is 50-90000 angstroms.

[0045] In an embodiment, the active layer 103 is a periodic structure composed of well layers and barrier layers, the period of the periodic structure is s: 1≤s≤10, the well layer of the active layer 103 is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, the thickness is t: 5≤t≤100 angstroms, and the light emitting wavelength is 500-1600 nm, and the barrier layer of the active layer 103 is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, the thickness is u: 10≤u≤200 angstroms.

[0046] In one embodiment, the lower waveguide layer 102 is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of v: 10≤v≤9000 angstroms; the upper waveguide layer 104 is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of w: 10≤w≤9000 angstroms; the lower confinement layer 101 is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of r: 10≤r≤90000 angstroms; the upper confinement layer 106 and the electron blocking layer 105 are any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness of g: 10≤g≤80000 angstroms.

[0047] In one embodiment, the substrate 100 is any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO2 composite substrate 100, sapphire / AlN composite substrate 100, sapphire / SiNx, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate 100.

[0048] Referring to Figures 2-3 , respectively, are a SIMS secondary ion mass spectrum and another SIMS secondary ion mass spectrum provided by embodiments of the present application.

[0049] Referring to Figures 4-5 , respectively, are a TEM lens electron microscope image of the lower confinement layer 101 and a TEM lens electron microscope image of the active layer 103 provided by embodiments of the present application.

[0050] The embodiments of the present application have the following beneficial effects:

[0051] In the embodiment of the present application, by designing the lattice constant of the well layer to be greater than or equal to the lattice constant of the barrier layer, the thermal expansion coefficient of the well layer to be less than or equal to the thermal expansion coefficient of the barrier layer, and the elastic coefficient of the well layer to be less than or equal to the elastic coefficient of the barrier layer, the carrier capture effect, deep level defects and insulating interface of the depletion region of the active layer 103 of the semiconductor laser can be effectively controlled, so that the symmetry breaking of the laser principle equilibrium state phase transition can be inhibited, and then the sudden change phenomenon of the laser at the threshold can be effectively solved, and the problems such as the conductance jump, the capacitance deep drop and the junction voltage jump can be eliminated.

[0052] The above is the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements are also considered to be within the scope of protection of the present application.

Claims

1. A semiconductor laser, characterized in that, include: The layers arranged from bottom to top are: substrate, lower confinement layer, lower waveguide layer, active layer, upper waveguide layer, electron blocking layer, and upper confinement layer. The active layer includes a well layer and a barrier layer; The lattice constant, thermal expansion coefficient, and elastic modulus of the active layer all exhibit a U-shaped distribution. The In / C element ratio of the active layer exhibits an inverted U-shaped distribution; The lattice constant of the well layer is greater than or equal to the lattice constant of the barrier layer; The thermal expansion coefficient of the well layer is less than or equal to the thermal expansion coefficient of the barrier layer; The elastic coefficient of the trap layer is less than or equal to the elastic coefficient of the barrier layer.

2. The semiconductor laser as described in claim 1, characterized in that, The number of periods m of the active layer satisfies 1≤m≤3.

3. The semiconductor laser as described in claim 1, characterized in that, The active layer well layer includes at least one of InGaN, InN, GaN, AlInGaN, AlInN, and AlGaN, and the active layer well layer thickness is 10~200 angstroms, and the emission wavelength is 200~500 nm. The barrier layer of the active layer includes at least one of GaN, AlInGaN, AlInN, AlGaN, and AlN, and the barrier layer thickness of the active layer is 5 to 500 angstroms.

4. The semiconductor laser as described in claim 1, characterized in that, The lower waveguide layer is any one or any combination of InGaN, InN, GaN, AlInGaN, AlN, AlGaN, and AlInN, and the thickness of the lower waveguide layer is 10 to 5000 angstroms; the upper waveguide layer is any one or any combination of InGaN, InN, GaN, AlInGaN, AlInN, and AlGaN, and the thickness of the upper waveguide layer is 20 to 6000 angstroms; the upper confinement layer is any one or any combination of GaN, AlInGaN, AlN, AlInN, and AlGaN, and the thickness of the upper confinement layer is 20 to 50000 angstroms; the lower confinement layer is any one or any combination of GaN, AlInGaN, AlN, AlInN, and AlGaN, and the thickness of the lower confinement layer is 50 to 90000 angstroms.

5. The semiconductor laser as described in claim 1, characterized in that, The active layer is a periodic structure composed of a well layer and a barrier layer, and the period of the periodic structure is s: 1≤s≤10; the well layer of the active layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness t: 5≤t≤100 angstroms and an emission wavelength of 500~1600nm; the barrier layer of the active layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3 and BN, with a thickness u: 10≤u≤200 angstroms.

6. The semiconductor laser as claimed in claim 1, characterized in that, The lower waveguide layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3, and BN, with a thickness v: 10 ≤ v ≤ 9000 Å; the upper waveguide layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3, and BN, with a thickness w: 10 ≤ w ≤ 9000 Å; the lower limit The superposition layer is any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3, and BN, with a thickness r: 10 ≤ r ≤ 90000 angstroms; the upper confinement layer and the electron blocking layer are any one or any combination of GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, AlInAs, AlInP, AlGaP, InGaP, SiC, Ga2O3, and BN, with a thickness g: 10 ≤ g ≤ 80000 angstroms.

7. The semiconductor laser as claimed in claim 1, characterized in that, The substrate includes any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiNx, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

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