Gallium nitride-based semiconductor blue laser chip
By designing specific density distribution characteristics in the lower waveguide layer of the gallium nitride-based semiconductor blue laser chip, a lower waveguide layer that suppresses optical catastrophe is formed, the thermal degradation and optical catastrophe problems of nitride semiconductor laser are solved, and the radiation efficiency and life of the laser are improved.
Patent Information
- Application Number
- CN202510352712.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Nitride semiconductor lasers have problems such as high defect density inside the active layer, segregation of InN phase, and deterioration of thermal stability, resulting in non-uniform widening of the laser spectrum, reduced radiation efficiency and shortened lifetime.
A gallium nitride-based semiconductor blue light laser chip is designed. The lower waveguide layer adopts specific density distribution characteristics to form a lower waveguide layer that suppresses optical catastrophe to regulate the density distribution of the lower waveguide layer and suppress thermal degradation and thermal mismatch of the active layer.
Through the specific design of the density distribution of the lower waveguide layer, the thermal degradation and optical catastrophe of the laser are suppressed, the carrier drift uniformity and the laser thermal conductivity are improved, and the laser life is extended.
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Figure CN120127503A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor optoelectronic devices, and particularly to a gallium nitride-based semiconductor blue laser chip. Background Art
[0002] Lasers are widely used in the fields of laser display, laser TV, laser projector, communication, medical treatment, weapons, guidance, ranging, spectral analysis, cutting, precision welding, high-density optical storage, etc. There are many types of lasers and diverse classification methods. The main types include solid-state, gas, liquid, semiconductor, and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers have the advantages of small volume, high efficiency, light weight, good stability, long lifespan, 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 emission of carriers, with a relatively small spectral full width at half maximum, very high brightness, and the output power of a single laser can be in the watt level. While nitride semiconductor light-emitting diodes are spontaneous emission, and the output power of a single light-emitting diode is in the milliwatt level.
[0005] 2) The operating current density of lasers reaches kA / cm², which is more than two orders of magnitude higher than that of nitride light-emitting diodes, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect, and more serious electron-hole mismatch, leading to a more serious efficiency droop effect.
[0006] 3) Light-emitting diodes are spontaneous transition radiation, without external influence, and are incoherent light that transitions from a high energy level to a low energy level. While lasers are stimulated transition radiation, and the energy of the induced photon should be equal to the energy difference between the electron transitions, generating photons that are identical and coherent with the induced photons.
[0007] 4) The principles are different: Light-emitting diodes generate radiative recombination and emit light when electrons and holes transition to quantum wells or p-n junctions under the action of an external voltage. While lasers require lasing conditions to be met for lasing. It must satisfy the condition of carrier population inversion distribution in the active region. The stimulated emission light oscillates back and forth in the resonant cavity, and the propagation in the gain medium amplifies the light. When the threshold condition is met, the gain is greater than the loss, and finally, laser light is output.
[0008] The nitride semiconductor laser has the following problems: when the In composition of the quantum well of the laser increases, In-N segregation occurs at dislocations, resulting in two-dimensional island structures or three-dimensional island structures, leading to a high density of internal defects in the active layer, InN phase separation segregation, poor thermal stability, thermal degradation and lattice thermal mismatch in the active layer during the growth of high-temperature p-type semiconductors and confinement layers, reducing the quality of the active layer and the interface quality, as well as a large number of In-rich clusters, causing non-uniform broadening of the laser spectrum, increasing non-radiative recombination centers or optical catastrophes, reducing the radiative efficiency and shortening the laser lifetime. At the same time, the energy loss with a coupling rate of less than 1 from the pump energy level to the upper laser energy level is converted into heat, generating a large amount of waste heat, making the temperature distribution of the laser uneven, causing uneven thermal expansion and thermal stress distribution, resulting in temperature quenching, laser fracture or optical catastrophe. Summary of the Invention
[0009] To solve one of the above technical problems, the present invention provides a gallium nitride-based semiconductor blue laser chip.
[0010] An embodiment of the present invention provides a gallium nitride-based semiconductor blue laser chip, including a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper cladding layer arranged in sequence from bottom to top. The lower waveguide layer is a lower waveguide layer for suppressing optical catastrophe. The lower waveguide layer for suppressing optical catastrophe is any one or any combination of InGaN, GaN, InN, and AlInGaN. The lower waveguide layer for suppressing optical catastrophe has a density distribution characteristic, and the density of the lower waveguide layer for suppressing optical catastrophe is a function y 1 = x -a in a third quadrant curve distribution, where a > 1 and a is an odd number, and x is the depth of the lower waveguide layer for suppressing optical catastrophe towards the active layer.
[0011] Preferably, the density of the lower waveguide layer for suppressing optical catastrophe shows a downward trend towards the lower cladding layer, and the downward change angle is 40° to 90°.
[0012] Preferably, the lower waveguide layer for suppressing optical catastrophe also has a valence band effective density of states distribution characteristic, and the valence band effective density of states of the lower waveguide layer for suppressing optical catastrophe is a function y 2 = e x / x in a third quadrant curve distribution.
[0013] Preferably, the valence band effective density of states of the lower waveguide layer for suppressing optical catastrophe shows a downward trend towards the lower cladding layer, and the downward change angle is 40° to 90°.
[0014] Preferably, the lower waveguide layer for suppressing optical catastrophe also has a hole mobility distribution characteristic, and the hole mobility of the lower waveguide layer for suppressing optical catastrophe is a function y 3 = sinx / x 2 in a third quadrant curve distribution.
[0015] Preferably, the hole mobility of the waveguide layer under the suppression of optical catastrophe shows a downward trend in the direction of the lower cladding layer, and the downward change angle is from 50° to 90°.
[0016] Preferably, the waveguide layer under the suppression of optical catastrophe also has the characteristic of the light hole effective mass distribution, and the light hole effective mass of the waveguide layer under the suppression of optical catastrophe is a function y 4 = e x / x 2 Second quadrant curve distribution.
[0017] Preferably, the light hole effective mass of the waveguide layer under the suppression of optical catastrophe shows an upward trend in the direction of the lower cladding layer, and the upward change angle is from 50° to 90°.
[0018] Preferably, the active layer is a periodic structure composed of well layers and barrier layers, the number of periods is 3 ≥ m ≥ 1, 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, Ga 2 O 3 、BN, diamond, with a thickness of 10 angstroms to 150 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, Ga 2 O 3 、BN, diamond, with a thickness of 10 angstroms to 200 angstroms.
[0019] Preferably, the lower cladding layer, the upper waveguide 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, Ga 2 O 3 , BN, diamond, or any combination thereof.
[0020] Preferably, the substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO 2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, sapphire / SiN x 、sapphire / SiO 2 / SiN x composite substrate, sapphire / SiN x / SiO 2 composite substrate, magnesium aluminate spinel MgAl 2 O 4 , MgO, ZnO, ZrB 2 , LiAlO 2 and LiGaO 2 composite substrate, or any one thereof.
[0021] The beneficial effects of the present invention are as follows: The present invention specifically designs the density distribution characteristics in the lower waveguide layer of the gallium nitride-based semiconductor blue laser chip, so that the lower waveguide layer forms a lower waveguide layer that suppresses optical catastrophe, thereby regulating the density distribution of the lower waveguide layer, suppressing the thermal degradation and thermal mismatch of the active layer, reducing non-radiative recombination, suppressing optical catastrophe. At the same time, it improves the uniformity of carrier drift in the longitudinal, transverse, and lateral directions in the active region, improves the heat conduction efficiency of the laser cavity, reduces the internal heat accumulation in the laser, and improves the coupling rate of the pump light to the upper laser energy level, suppresses the waste heat and laser gain saturation, reduces the hole burning effect caused by the uneven thermal stress and refractive index increase-induced self-focusing and beam distortion, thereby suppressing optical catastrophe. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:
[0023] Figure 1 Schematic structural diagram of a gallium nitride-based semiconductor blue laser chip according to an embodiment of the present invention;
[0024] Figure 2 SIMS secondary ion mass spectrometry diagram of a gallium nitride-based semiconductor blue laser chip according to an embodiment of the present invention.
[0025] Reference numerals:
[0026] 100, substrate; 101, lower cladding layer; 102, lower waveguide layer; 103, active layer; 104, upper waveguide layer; 105, upper cladding layer. Detailed implementation manners
[0027] In order to make the technical solutions and advantages in the embodiments of the present application clearer and more understandable, the following further details the exemplary embodiments of the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.
[0028] As Figure 1 and Figure 2 shown, this embodiment provides a gallium nitride-based semiconductor blue laser chip, which includes a substrate 100, a lower cladding layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, and an upper cladding layer 105 arranged in sequence from bottom to top. Among them, the lower waveguide layer 102 is a lower waveguide layer 102 for suppressing optical catastrophe.
[0029] Specifically, in this embodiment, the gallium nitride-based semiconductor blue 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, and an upper cladding layer 105 in sequence from bottom to top. The lower waveguide layer 102 has a density distribution characteristic, specifically showing a curve distribution in the third quadrant of the function y 1 = x -a where a > 1 and a is an odd number, and x is the depth of the lower waveguide layer for suppressing optical catastrophe towards the active layer, showing a zigzag distribution, similar to a "7" - shaped distribution, so that the lower waveguide layer 102 forms a lower waveguide layer 102 for suppressing optical catastrophe.
[0030] In this embodiment, the density distribution characteristics in the lower waveguide layer are specifically designed, so that the lower waveguide layer forms a lower waveguide layer that suppresses optical catastrophe, thereby regulating the density distribution of the lower waveguide layer, suppressing the thermal degradation and thermal mismatch of the active layer, reducing non-radiative recombination, suppressing optical catastrophe. At the same time, it improves the longitudinal, lateral, and side drift uniformity of carriers in the active region, improves the thermal conductivity efficiency of the laser cavity, reduces the internal heat accumulation in the laser, and improves the coupling rate of pump light to the upper laser energy level, suppresses waste heat and laser gain saturation, reduces the hole burning effect caused by uneven thermal stress and refractive index increase-induced self-focusing and beam distortion, thereby suppressing optical catastrophe.
[0031] In some alternative embodiments, the density of the lower waveguide layer 102 that suppresses optical catastrophe also shows a certain change trend in the direction towards the lower cladding layer 101. Specifically, the density of the lower waveguide layer 102 that suppresses optical catastrophe shows a downward trend in the direction towards the lower cladding layer 101, specifically manifested as a steep downward trend, and the downward change angle is 40° to 90°, such as change angles of 40°, 50°, 60°, 70°, 80°, 90°, etc.
[0032] In some alternative embodiments, the lower waveguide layer 102 that suppresses optical catastrophe also has the valence band effective density of states distribution characteristics. The valence band effective density of states of the lower waveguide layer 102 that suppresses optical catastrophe is a function y 2 = e x / x third quadrant curve distribution, manifested as a broken line distribution, approximately in the shape of a "7" distribution. At the same time, the valence band effective density of states of the lower waveguide layer 102 that suppresses optical catastrophe also shows a certain change trend in the direction towards the lower cladding layer 101. Specifically, the valence band effective density of states of the lower waveguide layer 102 that suppresses optical catastrophe shows a downward trend in the direction towards the lower cladding layer 101, specifically manifested as a steep downward trend, and the downward angle is 40° to 90°, such as change angles of 40°, 50°, 60°, 70°, 80°, 90°, etc.
[0033] In some alternative embodiments, the lower waveguide layer 102 that suppresses optical catastrophe also has the hole mobility distribution characteristics. The hole mobility of the lower waveguide layer 102 that suppresses optical catastrophe is a function y 3 = sinx / x 2 third quadrant curve distribution, manifested as a broken line distribution, approximately in the shape of a "7" distribution. At the same time, the hole mobility of the lower waveguide layer 102 that suppresses optical catastrophe also shows a certain change trend in the direction towards the lower cladding layer 101. Specifically, the hole mobility of the lower waveguide layer 102 that suppresses optical catastrophe shows a downward trend in the direction towards the lower cladding layer 101, specifically manifested as a steep downward trend, and the downward angle is 50° to 90°, such as change angles of 50°, 60°, 70°, 80°, 90°, etc.
[0034] In some optional embodiments, the waveguide layer 102 under optical catastrophe suppression further has a light hole effective mass distribution characteristic, and the light hole effective mass of the waveguide layer 102 under optical catastrophe suppression is a function y 4 = e x / x 2 The second quadrant curve distribution is a broken line distribution, approximately an inverted "L" shape. At the same time, the light hole effective mass of the waveguide layer 102 under optical catastrophe suppression also shows a certain change trend in the direction of the underlying layer 101. Specifically, the light hole effective mass of the waveguide layer 102 under optical catastrophe suppression shows an upward trend in the direction of the underlying layer 101, specifically a steep upward trend, with an upward angle of 50° to 90°, such as change angles of 50°, 60°, 70°, 80°, 90°, etc.
[0035] In this embodiment, by specifically designing the distribution characteristics of the valence band effective density of states, hole mobility, and light hole effective mass of the waveguide layer 102 under optical catastrophe suppression, the density distribution of the lower waveguide layer can be further regulated, the thermal degradation and thermal mismatch of the active layer can be suppressed, non-radiative recombination can be reduced, optical catastrophe can be suppressed. At the same time, the carrier drift uniformity in the longitudinal, transverse, and lateral directions of the active region can be improved, the heat conduction efficiency of the laser cavity can be enhanced, the internal heat accumulation of the laser can be reduced, and the coupling rate of the pump light to the upper laser energy level can be increased, suppressing waste heat and laser gain saturation, reducing the hole burning effect caused by uneven thermal stress and refractive index increase-induced self-focusing and beam distortion, thereby suppressing optical catastrophe.
[0036] In some optional embodiments, the waveguide layer 102 under optical catastrophe suppression is any one or any combination of InGaN, GaN, InN, and AlInGaN.
[0037] In some optional embodiments, the active layer 103 is a periodic structure composed of well layers and barrier layers, with the number of periods 3 ≥ m ≥ 1. 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, any one or any combination of BN and diamond, with a thickness of 10 angstroms to 150 angstroms, and the stacked layers being 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 and diamond, with a thickness of 10 angstroms to 200 angstroms.
[0038] In some optional embodiments, the lower cladding layer 101, the upper waveguide layer 104, and the upper cladding 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, Ga 2 O 3 , any one or any combination of any one or any combination of BN and diamond.
[0039] In some optional embodiments, the substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO 2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, sapphire / SiN x , sapphire / SiO 2 / SiN x composite substrate, sapphire / SiN x / SiO 2 composite substrate, magnesium aluminate spinel MgAl 2 O 4 , MgO, ZnO, ZrB 2 , LiAlO 2 and LiGaO 2 any one of the composite substrates.
[0040] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.
Claims
1. A gallium nitride-based semiconductor blue laser chip, comprising a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper cladding layer arranged in sequence from bottom to top, characterized in that: The lower waveguide layer is an optical catastrophe suppression lower waveguide layer, and the optical catastrophe suppression lower waveguide layer is any one or any combination of InGaN, GaN, InN, and AlInGaN. The optical catastrophe suppression lower waveguide layer has a density distribution characteristic, and the density of the optical catastrophe suppression lower waveguide layer is a function y1=x -a The curve distribution of the third quadrant, a>1 and a is an odd number, and x is the depth of the waveguide layer toward the active layer under the suppression of optical catastrophe.
2. The gallium nitride-based semiconductor blue laser chip according to claim 1, characterized in that: The density of the waveguide layer for suppressing optical catastrophe shows a decreasing trend toward the lower cladding layer, and the decreasing angle is 40° to 90°.
3. The gallium nitride-based semiconductor blue laser chip according to claim 1, characterized in that: The optical catastrophe suppression waveguide layer also has a valence band effective state density distribution characteristic. The valence band effective state density of the optical catastrophe suppression waveguide layer is a function y2=e x / xThird quadrant curve distribution.
4. The gallium nitride-based semiconductor blue laser chip according to claim 3, characterized in that: The valence band effective state density of the waveguide layer under the optical catastrophe suppression method shows a downward trend toward the lower cladding layer, and the downward change angle is 40° to 90°.
5. The gallium nitride-based semiconductor blue laser chip according to claim 1, characterized in that: The optical catastrophe suppression waveguide layer also has a hole mobility distribution characteristic. The hole mobility of the optical catastrophe suppression waveguide layer is a function y3=sinx / x 2 The third quadrant curve distribution.
6. The gallium nitride-based semiconductor blue laser chip according to claim 5, characterized in that: The hole mobility of the waveguide layer under the optical catastrophe suppression shows a downward trend toward the lower cladding layer, and the downward change angle is 50° to 90°.
7. The gallium nitride-based semiconductor blue laser chip according to claim 1, characterized in that: The optical catastrophe suppression waveguide layer also has a light hole effective mass distribution characteristic. The light hole effective mass of the optical catastrophe suppression waveguide layer is a function y4=e x / x 2 Second quadrant curve distribution.
8. The gallium nitride-based semiconductor blue laser chip according to claim 7, characterized in that: The light hole effective mass of the waveguide layer for suppressing optical catastrophe increases toward the lower cladding layer, and the rising angle is 50° to 90°.
9. The gallium nitride-based semiconductor blue 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, BN, and diamond , with a thickness of 10 angstroms to 150 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 angstroms to 200 angstroms.
10. The gallium nitride-based semiconductor blue laser chip according to claim 1, characterized in that: The lower cladding layer, the upper waveguide 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, 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.