Laser chip and preparation method therefor, and laser module, optical module and laser device

Abstract

A laser chip (100) and a preparation method therefor, and a laser module (1000a), an optical module (1000b) and a laser device. The laser chip (100) comprises: at least two laser epitaxial structures (103), wherein in a first direction (X), the laser epitaxial structures (103) are sequentially and laterally arranged on a substrate (102) in a cascaded manner; and an n-type electrode (101) and p-type electrodes (104), wherein one is located on the side of the substrate (102) away from the laser epitaxial structures (103) in a second direction (Y), and the other one is located on the side of the laser epitaxial structures (103) away from the substrate (102) in the second direction (Y). In this way, on the basis of the architecture of the laser chip (100), the laser epitaxial structures (103) can be respectively provided corresponding to three primary colors, i.e., RGB, so as to realize lasing at different wavelengths; the laser epitaxial structures (103) corresponding to the three primary colors, i.e., RGB, are cascaded and integrated on a single chip, such that white-light output from a single chip is realized; no beam coupling arrangement is required at the rear end of a light source module, and thus the cost and size can be further reduced; in addition, lasing at different wavelengths can also be achieved for the same primary color, and thus speckles in a projection scenario can be effectively mitigated.

Description

Laser chips and their fabrication methods, laser modules, optical modules and laser equipment

[0001] This application claims priority to Chinese Patent Application No. 202510387964.4, filed with the State Intellectual Property Office of China on March 27, 2025, entitled "Laser Chip and Preparation Method Thereof, Laser Module, Optical Module and Laser Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of semiconductor technology, and in particular to a laser chip and its fabrication method, a laser module, an optical module, and a laser device. Background Technology

[0003] Among third-generation semiconductor materials, group III nitrides possess characteristics such as large bandgap, high breakdown voltage, high thermal conductivity, high electron saturation drift velocity, and strong chemical stability, and have found applications in the laser field, meeting the requirements of laser display / projection light source modules. A typical gallium nitride (GaN) chip structure includes, from bottom to top, an n-type electrode, an n-type GaN substrate, a laser epitaxial structure, and a p-type electrode, forming a single-wavelength laser chip. To achieve high power, it is usually necessary to increase the operating current, which leads to problems such as reduced luminous efficiency, increased heat dissipation, decreased efficiency, and increased substrate size. For applications integrating red (R), green (G), and blue (B) primary colors, three or more laser chips of different wavelengths need to be configured in the same light source module; at the same time, due to the physical separation of the RGB primary color beams, multiple mirrors and prisms are needed at the back end of the module for beam combining to reduce the beam spacing, making it impossible to reasonably control the chip configuration cost and the size and cost of the module.

[0004] Furthermore, due to the single-wavelength characteristics of this chip architecture, coupled with the high coherence of lasers, speckle issues arise when applied in projection scenarios, affecting the visual effect. Summary of the Invention

[0005] This application provides a laser chip and its fabrication method, a laser module, an optical module, and a laser device. Through structural optimization of the chip architecture, while increasing power, it can effectively improve the speckle that may be generated by a single wavelength, and provides a good technical guarantee for reasonably controlling product size and implementation cost.

[0006] The first aspect of this application provides a laser chip, which includes an n-type electrode, a substrate, a laser epitaxial structure, and a p-type electrode. At least two laser epitaxial structures are cascaded sequentially on the substrate in a first direction, which is a direction within the plane of the substrate. One of the n-type and p-type electrodes is located on the side of the substrate away from the laser epitaxial structure in a second direction, and the other is located on the side of the laser epitaxial structure away from the substrate in the second direction. The second direction is the direction intersecting the plane of the substrate. With this configuration, laser epitaxial structures can be set for each of the RGB primary colors to achieve lasing at different wavelengths. By cascading and integrating the RGB primary color laser epitaxial structures on a single chip, monolithic white light output can be achieved. This allows for reasonable control of chip configuration costs. Furthermore, compared to solutions using multiple single-wavelength laser chips, the laser chip architecture provided in this application allows for monolithic white light output, further reducing the implementation cost of the light source module. Moreover, the back end of the light source module does not require beam coupling, further reducing module cost and size.

[0007] In addition, based on this laser chip architecture, at least two laser epitaxial structures can be set for the same primary color, and different wavelengths of lasing can be achieved for the same primary color. This can effectively improve speckle in the projection scene. In other words, by appropriately widening the wavelength range, the perceptibility of speckle can be eliminated, thereby improving the user experience.

[0008] Furthermore, based on this laser chip architecture, the lasing wavelengths of each laser epitaxial structure can be the same. By cascading the laser epitaxial structures, high power requirements can be met, avoiding the problems of reduced optical efficiency, increased heat dissipation, and decreased efficiency that may result from increasing the power by increasing the operating current.

[0009] For example, both the substrate and the laser epitaxial structure can be made of group III nitrides.

[0010] Based on the first aspect, this application also provides a first implementation method of the first aspect: three laser epitaxial structures are configured, namely a first laser epitaxial structure, a second laser epitaxial structure, and a third laser epitaxial structure; the lasing wavelength of the third laser epitaxial structure is 600nm to 700nm, the lasing wavelength of the second laser epitaxial structure is 500nm to 570nm, and the lasing wavelength of the first laser epitaxial structure is 400nm to 470nm. Thus, RGB three-primary-color laser epitaxial structures are cascaded and integrated on a single chip, achieving reliable output of monolithic white light.

[0011] Based on the first aspect, this application also provides a second implementation of the first aspect: the lasing wavelength of each laser epitaxial structure corresponds to the same primary color, and the lasing wavelength spacing of each laser epitaxial structure is no greater than 10 nm. Therefore, achieving lasing with different wavelengths for the same primary color can effectively improve speckle in the projection scene, thereby further enhancing the user experience.

[0012] Based on the first aspect, or the first implementation of the first aspect, or the second implementation of the first aspect, this application also provides a third implementation of the first aspect: the substrate is an n-type substrate, the n-type electrode is electrically connected to the n-type substrate, and the laser epitaxial structure along the second direction includes, in sequence, an n-type buffer layer, an n-type confinement layer, an n-side waveguide layer, an active region, a p-side waveguide layer, a p-type confinement layer, and a p-type contact layer; the p-type electrode is electrically connected to the surface of the p-type contact layer away from the p-type confinement layer.

[0013] Based on the third implementation of the first aspect, this application also provides a fourth implementation of the first aspect: at least two p-type electrodes are provided, with each p-type electrode corresponding to a p-type contact layer. In this way, the p-type electrode side of each laser epitaxial structure is driven separately, thereby controlling the operating current.

[0014] Based on the third implementation of the first aspect, this application also provides a fifth implementation of the first aspect: at least two p-type contact layers of laser epitaxial structures can also be electrically connected to the same p-type electrode. Overall, this further enables more reasonable control over the manufacturing cost of the device.

[0015] Based on the third, fourth, or fifth implementation of the first aspect, this application also provides a sixth implementation of the first aspect: the active region includes one or more quantum well structures, and the material of the quantum well structure is Al. x2 In y2 Ga (1-x2-y2) N, the material of the quantum barrier is Al x3 In y3 Ga (1-x3-y3) N, where 0≤x2≤1, 0≤y2≤1, 0≤x3≤1, 0≤y3≤1, 0≤(x2+y2)≤1, 0≤(x3+y3)≤1. Thus, by adjusting the material composition and thickness of the quantum wells, the lasing wavelength can be precisely controlled. This can be achieved by incorporating In components into a multi-quantum-well structure and shaping them accordingly.

[0016] For example, y2≥y3≥0.1.

[0017] Based on the third, fourth, fifth, or sixth implementation of the first aspect, this application also provides a seventh implementation of the first aspect: the material of the n-type confinement layer, the n-side waveguide layer, the active region, the p-side waveguide layer, the p-type confinement layer, and / or the p-type contact layer is Al. x1 In y1 Ga (1-x1-y1) N, where 0≤x1≤1, 0≤y2≤1, and 0≤(x1+y1)≤1.

[0018] Based on the third, fourth, fifth, sixth, or seventh implementation of the first aspect, this application also provides an eighth implementation of the first aspect: a trench is provided between two adjacent laser epitaxial structures, and an insulating dielectric layer is filled in the trench. The dimensions of the trench are configured as follows: the width is 1um to 100um, the length is 100um to 2000um, and the depth is 1um to 10um.

[0019] Based on the eighth embodiment of the first aspect, this application also provides a ninth embodiment of the first aspect: interconnecting the n-type buffer layers of two adjacent laser epitaxial structures. This enables reliable cascading of each laser epitaxial structure onto an n-type substrate.

[0020] Based on the first aspect, or the first embodiment of the first aspect, or the second embodiment of the first aspect, or the third embodiment of the first aspect, or the fourth embodiment of the first aspect, or the fifth embodiment of the first aspect, or the sixth embodiment of the first aspect, or the seventh embodiment of the first aspect, or the eighth embodiment of the first aspect, or the ninth embodiment of the first aspect, this application also provides a tenth embodiment of the first aspect: the laser chip further includes a mask layer, the mask layer is located above the substrate, the mask layer has windows corresponding to each laser epitaxial structure, and each laser epitaxial structure is located on the substrate on which the mask layer is provided. In this way, by adjusting the size of the windows in the mask layer, the control of stress during the secondary epitaxy process can be improved, thereby controlling the bending or tilting of the active region quantum well band and achieving wavelength change. That is, by adjusting the width of the mask layer and the size of the windows, the stress generated during the growth of the laser epitaxial structure can be adjusted to obtain the corresponding lasing wavelength.

[0021] Based on the tenth embodiment of the first aspect, this application also provides an eleventh embodiment of the first aspect: in the second direction, the geometric center line of the window is offset from the geometric center line of the waveguide of the corresponding laser epitaxial structure. In this way, by reducing the dislocation density in the upper laser functional layer through dislocation bending, annihilation, etc., the impact of dislocation propagation on laser performance and reliability can be effectively avoided.

[0022] A second aspect of this application provides a laser module comprising a laser chip, a circuit board, a reflector, and a housing. The laser chip is the laser chip described above, the housing is mounted on the circuit board, and the compatible laser chip and reflector are located inside the housing. This laser module, with its aforementioned laser chip, also reduces cost and size, effectively improves speckle in projection scenes, and avoids the problems that may arise from increasing power by increasing operating current, such as reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate.

[0023] A third aspect of this application provides an optical module comprising a driver chip and a laser chip. The laser chip is the laser chip described above, and the output terminal of the driver chip is electrically connected to the laser chip. Based on the aforementioned laser chip, this optical module also has the advantages of reducing cost and size, effectively improving speckle in projection scenes, and avoiding the problems of reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate that may result from increasing power by increasing operating current.

[0024] A fourth aspect of this application provides a laser device, which includes an optical component and an optical module. The optical module is as described above, and the optical component is used to adjust the optical parameters of the laser output by the optical module. Based on the aforementioned laser chip, this optical module also has the advantages of reducing cost and size, effectively improving speckle in projection scenes, and avoiding the problems that may result in reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrates caused by increasing power through increased operating current.

[0025] The fifth aspect of this application provides a method for fabricating a laser chip, the laser chip including at least two laser epitaxial structures, the at least two laser epitaxial structures being cascaded sequentially on a substrate in a first direction, the first direction being a direction within the plane of the substrate; the fabrication method includes the following steps: forming at least two laser epitaxial structures on the substrate by multiple selective region epitaxial growth.

[0026] Based on the fifth aspect, this application also provides a first implementation of the fifth aspect: forming at least two laser epitaxial structures through multiple selective area epitaxial growth, including: growing a first epitaxial structure layer by layer corresponding to one of the laser epitaxial structures, the first epitaxial structure covering the entire surface of the substrate; removing a portion of the first epitaxial structure to form a reserved region corresponding to one of the laser epitaxial structures; covering the top of the reserved region with a protective layer; growing corresponding epitaxial structures again layer by layer for the other laser epitaxial structures in the at least two laser epitaxial structures, until the complete laser epitaxial structure is grown; and removing the protective layer. This allows for reasonable control of laser chip cost and size, effectively improves speckle in projection scenes, and avoids problems such as reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate that may result from increasing power by increasing operating current.

[0027] Based on the fifth aspect, this application also provides a second implementation of the fifth aspect: multiple selective epitaxial growth to form at least two laser epitaxial structures, including: growing a bottom layer structure to form each laser epitaxial structure; etching a mask layer to form windows corresponding to each laser epitaxial structure; and epitaxially growing a functional layer to form each laser epitaxial structure. In this way, by adjusting the size of the windows in the mask layer, stress control during the secondary epitaxy process is improved, thereby controlling the bending or tilting of the quantum well bandgap in the active region, that is, adjusting the stress generated during the growth of the laser epitaxial structure to obtain the corresponding lasing wavelength. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the architecture of a laser chip provided in an embodiment of this application;

[0029] Figure 2 is a schematic diagram showing the relative positional relationship of the laser epitaxial structure shown in Figure 1;

[0030] Figure 3 is a schematic diagram of the architecture of another laser chip provided in an embodiment of this application;

[0031] Figure 4 is a schematic diagram of the architecture of another laser chip provided in an embodiment of this application;

[0032] Figure 5 is a simplified process flow diagram of a laser epitaxial structure provided in an embodiment of this application;

[0033] Figure 6 is a simplified process flow diagram of another laser epitaxial structure provided in an embodiment of this application;

[0034] Figure 7 is a schematic diagram of the architecture of another laser chip provided in an embodiment of this application;

[0035] Figure 8 is a simplified process flow diagram of another laser epitaxial structure provided in the embodiments of this application;

[0036] Figure 9 is a schematic diagram of a laser module provided in an embodiment of this application;

[0037] Figure 10 is a schematic diagram of an optical module provided in an embodiment of this application. Detailed Implementation

[0038] This application provides a monolithic, horizontally stacked laser chip architecture implementation scheme, which can effectively improve speckle that may be generated by a single wavelength while increasing power, and provides technical assurance for reasonably controlling the size and implementation cost of RGB three-primary-color integrated products.

[0039] Group III nitrides possess characteristics such as large band gaps, high breakdown voltages, high thermal conductivity, high electron saturation drift velocities, and strong chemical stability, enabling them to withstand high power. Here, "Group III nitrides" refers to compounds formed from elements in Group III of the periodic table (such as gallium, indium, and aluminum) and nitrogen from Group V. Examples include, but are not limited to, single-component compounds such as aluminum nitride (AlN), indium nitride (InN), or gallium nitride (GaN), or multi-component compounds such as indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or indium gallium aluminum nitride (InGaN / AlGaN). Group III nitrides are direct bandgap materials with continuously tunable band gaps between 0.7 eV (InN) and 6.2 eV (AlN), emitting wavelengths covering the near-infrared, visible, and deep ultraviolet ranges. Therefore, it has been effectively applied in the field of lasers, possessing advantages such as good directionality, high brightness, long lifespan, wide color gamut, and high efficiency under high current. It has broad prospects in fields such as, but not limited to, laser display, laser lighting, and industrial processing. It can meet the needs of laser display and projection light source modules.

[0040] With the development of laser technology, high luminous efficiency, three-color integration, small size, and low cost have become the evolutionary trends of laser source modules. In related technologies, a typical GaN chip includes an n-type electrode, an n-type GaN substrate, a laser epitaxial structure, and a p-type electrode arranged sequentially from bottom to top, forming a single-wavelength laser chip. Based on this single-wavelength laser chip, the laser epitaxial structure can be optimized to improve power; however, the potential for power improvement is limited. To achieve high power, it is usually necessary to increase the operating current, which leads to a series of problems such as reduced luminous efficiency, increased heat dissipation, decreased efficiency, and increased substrate size.

[0041] Furthermore, based on this single-wavelength laser chip, for integrated RGB three-primary-color applications, the light source module needs to be configured with three or more laser chips of different wavelengths, and multiple reflectors and prisms need to be set at the rear of the module to couple the physically separated RGB three-primary-color beams. This makes it impossible to reasonably control the chip configuration cost, as well as the size and cost of the module.

[0042] Furthermore, due to the high coherence characteristics of the laser in this chip, there is a significant speckle problem when used in projection applications, affecting the visual effect. Speckle is usually eliminated by methods such as optical engine jitter and screen jitter, which requires additional design and implementation costs.

[0043] Based on this, this application provides a laser chip, which includes an n-type electrode, a substrate, a laser epitaxial structure, and a p-type electrode. The laser epitaxial structure is located above the substrate, and at least two laser epitaxial structures are configured. These at least two laser epitaxial structures are cascaded sequentially on the substrate in a first direction. One of the n-type electrode and the p-type electrode is located on the side of the substrate away from the laser epitaxial structure in a second direction, and the other is located on the side of the laser epitaxial structure away from the substrate in the second direction. The second direction is the direction intersecting the plane containing the substrate. Here, the materials of the substrate and the laser epitaxial structure are group III nitrides.

[0044] With this configuration, based on the laser chip architecture, laser epitaxial structures can be set up separately for each of the RGB primary colors to achieve lasing at different wavelengths. By cascading and integrating the RGB primary color laser epitaxial structures on a single chip, monolithic white light output can be achieved. This allows for reasonable control of chip configuration costs. Furthermore, compared to solutions using multiple single-wavelength laser chips, the laser chip architecture provided in this application can achieve white light output on a single chip, further reducing the implementation cost of the light source module. Moreover, the light source module does not require beam coupling at the rear end, further reducing module cost and size.

[0045] In addition, based on this laser chip architecture, at least two laser epitaxial structures can be set for the same primary color, and different wavelengths of lasing can be achieved for the same primary color. This can effectively improve speckle in the projection scene. In other words, by appropriately widening the wavelength range, the perceptibility of speckle can be eliminated, thereby improving the user experience.

[0046] Furthermore, based on this laser chip architecture, the lasing wavelengths of each laser epitaxial structure can be the same. By cascading the laser epitaxial structures, high power requirements can be met, avoiding the problems of reduced optical efficiency, increased heat dissipation, and decreased efficiency that may result from increasing the power by increasing the operating current.

[0047] To better understand the technical solutions and effects of this application, without loss of generality, specific embodiments will be described in detail below with reference to the accompanying drawings. Please refer to Figure 1, which is a schematic diagram of the architecture of a laser chip provided in an embodiment of this application.

[0048] As shown in Figure 1, the laser chip 100 includes an n-type electrode 101, an n-type substrate 102, a laser epitaxial structure 103, and a p-type electrode 104. For ease of description, the figure uses the symbol X to indicate a first direction, which is a direction located in the plane of the n-type substrate 102, i.e., a transverse direction; and uses the symbol Y to indicate a second direction, which is the direction intersecting the plane of the n-type substrate 102, i.e., the longitudinal direction of the laser epitaxial structure grown layer by layer based on the substrate epitaxy. For example, the second direction Y shown in the figure is approximately perpendicular to the first direction X.

[0049] In the second direction Y, the n-type substrate 102 is located above the n-type electrode 101, the laser epitaxial structure 103 is located above the n-type substrate 102, and the p-type electrode 104 is located above the laser epitaxial structure 103. In other words, the n-type electrode 101, the n-type substrate 102, the laser epitaxial structure 103, and the p-type electrode 104 are arranged sequentially in the second direction Y.

[0050] As shown in the figure, the laser chip 100 includes three laser epitaxial structures 103, namely a first laser epitaxial structure 103a, a second laser epitaxial structure 103b, and a third laser epitaxial structure 103c. In the first direction X, the first laser epitaxial structure 103a, the second laser epitaxial structure 103b, and the third laser epitaxial structure 103c are cascaded sequentially on an n-type substrate 102; and an insulating dielectric layer 105 is disposed on the side of each laser epitaxial structure 103.

[0051] In the specific implementation, each laser epitaxial structure 103 is grown from the same n-type substrate 102. Please refer to Figures 1 and 2 together, where Figure 2 is a schematic diagram of the relative positional relationship of the laser epitaxial structures shown in Figure 1. A trench 103-1 is formed between two adjacent laser epitaxial structures 103, and an insulating dielectric layer 105 fills the trench 103-1. The size of the trench 103-1 can be determined according to the overall product design requirements. For example, but not limited to, the width W1 of each trench 103-1 can be 1µm to 100µm, the length L1 can be 100µm to 2000µm, and the depth H1 can be 1µm to 10µm. The specific dimensions can be determined according to the overall product design requirements, and this embodiment does not limit the specific dimensions.

[0052] In other specific implementations, in the first direction X, the laser chip 100 may further include two laser epitaxial structures 103 (not shown in the figure) cascaded sequentially on the n-type substrate 102. In other possible implementations, the laser chip 100 may also include a plurality of other laser epitaxial structures 103 (not shown in the figure) cascaded sequentially on the n-type substrate 102, which may be determined according to the overall product design requirements, and are not limited in the embodiments of this application.

[0053] In this embodiment, the n-type electrode 101 can make full-surface contact with the thinned and polished n-type substrate 102 for reliable electrical connection. For example, but not limited to, the thickness of the n-type electrode 101 can be 5nm to 3000nm. The p-type electrodes 104 are arranged in a one-to-one correspondence with the laser epitaxial structure 103, that is, there are three p-type electrodes 104: a first p-type electrode 104a, a second p-type electrode 104b, and a third p-type electrode 104c. The first p-type electrode 104a is located above the first laser epitaxial structure 103a, the second p-type electrode 104b is located above the second laser epitaxial structure 103b, and the third p-type electrode 104c is located on the third laser epitaxial structure 103c. In this way, the p-type electrode side of each laser epitaxial structure 103 is driven separately to control the operating current.

[0054] It is understood that the materials of the p-type electrode 104 and the n-type electrode 101 include, but are limited to, any one or a combination of two or more of Ni, Ti, Pd, Pt, Au, Al, TiN, ITO and IGZO.

[0055] In other possible implementations, the configuration of the p-type electrode 104 is not limited to a one-to-one correspondence with the laser epitaxial structure 103. Taking three laser epitaxial structures 103 as an example, one configuration is that all three laser epitaxial structures 103 are driven by a single p-type electrode 104. Another configuration is that two of the three laser epitaxial structures 103 are driven by a single p-type electrode 104, while the third laser epitaxial structure 103 is driven by a single p-type electrode.

[0056] In this embodiment, for two or three laser epitaxial structures 103 that are driven by a single p-type electrode 104, the wavelengths can be the same or different. Specifically, different wavelengths of lasing can be achieved by adjusting the quantum well active region and other supporting epitaxial regions of each laser epitaxial structure 103. The specific determination can be made according to the overall product requirements, and this embodiment does not limit it.

[0057] In a specific implementation, a p-type thick gold electrode 106 can be covered on the p-type electrode 104. As shown in Figure 1, the p-type thick gold electrode 106 is electrically connected to the p-type electrode 104 to improve the stability and reliability of current injection.

[0058] The insulating dielectric layer 105 material includes, but is limited to, SiO2 and SiN. x (x=0~1), any one of SiON, Al2O3, AlON, SiAlON, TiO2, Ta2O5, ZrO2 and polycrystalline silicon, or a combination of two or more.

[0059] To further optimize beam quality and reduce threshold current, as shown in Figure 2, the top (P-side) of each laser epitaxial structure 103 is a strip waveguide 103-2. The dimensions of this waveguide 103-2 can be determined according to the overall product design requirements. For example, but not limited to, the waveguide width W2 of each laser can be 1µm to 100µm, the length L2 can be 100µm to 2000µm, and the height H2 can be 0.2µm to 2000nm. In addition, to balance the effects of manufacturing cost and device heat dissipation (junction temperature), the width W2 of waveguide 103-2 and the spacing T1 of waveguide 103-2 can meet the condition: 1% ≤ W2 / T1 ≤ 20%.

[0060] Alternatively, a chip-on-carrier (COC) process can be used to package the chip onto the substrate. Please refer to Figure 3, which is a schematic diagram of another laser chip architecture provided in an embodiment of this application. To clearly illustrate the differences and connections between this embodiment and the foregoing embodiments, identical functional components or structures are shown with the same reference numerals in the figure.

[0061] Compared to the laser epitaxial structure described in FIG1, the difference in this embodiment is that it also includes a heat dissipation substrate 107, as shown in FIG3, which is located above the p-type thick gold electrode 106. The heat dissipation substrate 107 provides good heat dissipation, and its surface can be patterned to accommodate the separate driving operation of multiple laser epitaxial structures.

[0062] In specific implementations, the material of the heat dissipation substrate 107 can be any one of silicon substrate (Si), aluminum nitride substrate (AlN), silicon carbide substrate (SiC), diamond, etc. The specific material can be determined according to the overall product design requirements, and this application embodiment does not impose any limitations.

[0063] The specific implementation of other functional components can adopt the same implementation method as the aforementioned embodiments. Further details will not be provided here.

[0064] In a specific implementation, the n-type substrate 102 serves as the basis for epitaxial structure growth and can be an n-type group III nitride single-crystal substrate to ensure the stable formation of the laser epitaxial structure. For example, the n-type substrate 102 can be an n-type GaN single-crystal substrate, specifically formed using a metal-organic chemical vapor deposition (MOCVD) process. Please refer to Figure 4, which is a schematic diagram of another laser chip architecture provided in this embodiment. To clearly illustrate the differences and connections between this embodiment and the schemes described in Figures 1 and 3, identical functional components or structures are indicated by the same labels in the figures.

[0065] As shown in Figure 4, based on the n-type substrate 102, each laser epitaxial structure 103 includes, along the second direction Y, an n-type buffer layer 1031, an n-type confinement layer 1032, an n-side waveguide layer 1033, an active region 1034, a p-side waveguide layer 1035, a p-type confinement layer 1036, and a p-type contact layer 1037.

[0066] The n-type buffer layers 1031 of the first laser epitaxial structure 103a, the second laser epitaxial structure 103b, and the third laser epitaxial structure 103c can be interconnected in the first direction X, so that each laser epitaxial structure 103 is cascaded on the n-type substrate 102.

[0067] Among them, each p-type electrode 104 (first p-type electrode 104a, second p-type electrode 104b, third p-type electrode 104c) is electrically bonded to the surface of the corresponding p-type contact layer 1037 (first p-type contact layer, second p-type contact layer, third p-type contact layer) away from the p-type confinement layer 1036.

[0068] The n-type electrode 101 is connected to the negative terminal (GND) of the driving circuit (not shown in the figure), and the p-type electrode 104 is connected to the positive terminal of the driving circuit. Under the action of the external driving circuit, current is injected into the active region 1034 of each laser epitaxial structure 103 through the pn junction. Electrons and holes recombine in the active region 1034 to release photons, and the photon wavelength is determined by the bandgap of the material. Under specific conditions, the holes and electrons are in an excited state. When a photon encounters an excited electron, it causes it to transition to a lower energy state and releases two photons with the same frequency and phase direction, forming stimulated emission. Laser light can be realized when the gain generated by the stimulated emission process exceeds the loss and the number of photons in the optical resonant cavity reaches the threshold. The p-side waveguide layer 1035 and the n-side waveguide layer 1033 are located on the upper and lower sides of the active region 1034, respectively, to limit the propagation direction of light. The propagation of light in the active region 1034 is limited by the difference in refractive index. The p-type confinement layer 1036 is located outside the p-side waveguide layer 1035 (away from the active region), and the n-type confinement layer 1032 is located outside the n-side waveguide layer 1033 (away from the active region), used to further confine the propagation of light and prevent light leakage.

[0069] In a specific implementation, the active region 1034 may include one or more quantum well structures, each including a quantum well and quantum barriers located on both sides of the quantum well, which restrict the escape of electrons and holes from the quantum well.

[0070] The p-type contact layer 1037 is located above the p-type confinement layer 1036 to achieve good electrical contact with the p-type electrode 104, thereby reducing contact resistance and ensuring efficient current injection into the active region 1034. Here, the materials of the p-type contact layer 1037, n-type confinement layer 1032, n-side waveguide layer 1033, active region 1034, p-side waveguide layer 1035, and p-type confinement layer 1036 can be group III nitrides. Specifically, they can include Al. x1 In y1 Ga (1-x1-y1) N, where x1 and y1 are both greater than or equal to 0 and less than or equal to 1, and satisfy: 0 ≤ (x1 + y1) ≤ 1. Preferably, the material of the p-type contact layer 1037 includes Al. x1 In y1 Ga (1-x1-y1) N, where x1 = 0, 0 ≤ y1 ≤ 0.5.

[0071] In a specific implementation, each p-type contact layer 1037 can be the same contact layer or different contact layers.

[0072] The n-type buffer layer 1031 is the interface layer connecting the laser epitaxial structure 103 and the n-type substrate 102. The n-type buffer layer 1031 can improve the epitaxial growth stress and ensure the crystal quality of the laser chip.

[0073] For the laser epitaxial structure 103, based on the n-type confinement layer 1032, the n-side waveguide layer 1033, the active region 1034, the p-side waveguide layer 1035, and the p-type confinement layer 1036, other epitaxial structure layers can be configured according to actual needs.

[0074] In a specific implementation, an electron blocking layer (EBL) (not shown in the figure) can be provided between the p-type confinement layer 1036 and the p-type contact layer 1037 to further prevent electrons from overflowing from the active region 1034 to the p-type region, ensuring carrier confinement efficiency and improving the efficiency and performance of the laser.

[0075] In one possible implementation, an n-type contact layer (not shown in the figure) can be selectively configured as needed and stacked sequentially to form the corresponding laser epitaxial structure. This can satisfy the functional design requirements of different devices, and the embodiments in this application are not limited thereto.

[0076] In this embodiment, the lasing wavelengths of each laser epitaxial structure 103 can be the same or different. Preferably, for different wavelength configurations, the wavelength of the third laser epitaxial structure 103c is greater than or equal to the wavelength of the second laser epitaxial structure 103b, which is greater than or equal to the wavelength of the first laser epitaxial structure 103a. In other words, the wavelengths of each laterally cascaded laser epitaxial structure 103 can increase sequentially.

[0077] For example, the three laser epitaxial structures 103 with different lasing wavelengths can correspond to the wavelengths of the three primary colors RGB respectively. The wavelength of the third laser epitaxial structure 103c is 600nm~700nm (red), the wavelength of the second laser epitaxial structure 103b is 500nm~570nm (green), and the wavelength of the first laser epitaxial structure 103a is 400nm~470nm (blue).

[0078] For example, three laser epitaxial structures 103 with different lasing wavelengths can each correspond to different wavelengths under any monochromatic RGB light. Taking the three-wavelength synthesis of green light as an example, the wavelength of the third laser epitaxial structure 103c is 530nm, the wavelength of the second laser epitaxial structure 103b is 525nm, and the wavelength of the first laser epitaxial structure 103a is 520nm, which is used to achieve the function of eliminating speckle. Furthermore, when the lasing wavelengths of each laser epitaxial structure 103 correspond to different wavelengths of the same primary color, the wavelength spacing is no greater than 10nm, which can obtain a better speckle elimination effect.

[0079] Of course, for other numbers of laser epitaxial structures 103, the wavelength can also be configured according to product design requirements. This application does not limit the embodiments.

[0080] In the foregoing embodiments, each laser epitaxial structure 103 of the laser chip can be formed by multiple selective epitaxy to create laser epitaxial structures with different wavelengths in the lateral direction (first direction X). Please refer to Figure 5, which is a simplified process flow diagram of a laser epitaxial structure provided in an embodiment of this application.

[0081] As shown in Figure 5, the process steps of multiple selective epitaxial growth are illustrated by three laser epitaxial structures 103.

[0082] In step S501, a first epitaxial structure 50a is formed by growing layer by layer on the n-type substrate 102 corresponding to the functional layer of the first laser epitaxial structure 103a. Here, the first epitaxial structure 50a covers the entire surface of the n-type substrate 102.

[0083] In practice, the growth of laser epitaxial structures can be achieved using one of the following methods: metal-organic chemical vapor deposition (MOCVD), atmospheric pressure chemical vapor deposition (APCVD), or molecular beam epitaxy (MBE).

[0084] Step S502: Remove a portion of the first epitaxial structure 50a and clean it. Corresponding to the positions of the second laser epitaxial structure 103b and the third laser epitaxial structure 103c, remove a portion of the first epitaxial structure 50a, retaining another portion of the first epitaxial structure 50a corresponding to the first laser epitaxial structure 103a, and then perform surface cleaning.

[0085] Here, after removing a portion of the first epitaxial structure 50a, structural layers near the n-type substrate 102 can be retained for the second laser epitaxial structure 103b and the third laser epitaxial structure 103c. For example, but not limited to, an n-type buffer layer 1031 and / or an n-type contact layer can be retained. The second laser epitaxial structure 103b and the third laser epitaxial structure 103c are grown based on the retained n-type buffer layer 1031 and / or n-type contact layer to achieve reliable cascading of each laser epitaxial structure 103. Furthermore, without affecting the subsequent growth processes of the second laser epitaxial structure 103b and the third laser epitaxial structure 103c, the removal process has a certain tolerance, resulting in good overall processability.

[0086] Of course, in other implementations, the structural layers near the n-type substrate 102 may not be retained corresponding to the second laser epitaxial structure 103b and the third laser epitaxial structure 103c; in other words, the portions of the first epitaxial structure 50a corresponding to the second laser epitaxial structure 103b and the third laser epitaxial structure 103c are completely removed, and the second laser epitaxial structure 103b and the third laser epitaxial structure 103c are grown based on the n-type substrate 102. In other possible implementations, for example, in the case where each laser epitaxial structure corresponds to a different wavelength of the same primary color, the structure from the n-type confinement layer to the n-type contact layer may be retained, and the other functional layers of the second laser epitaxial structure 103b and the third laser epitaxial structure 103c are grown based on the retained n-type confinement layer. The specific choice can be made according to the specific process conditions, and this application embodiment does not limit the specific implementation.

[0087] In practice, the removal methods include, but are limited to, any one of the material removal processes such as dry etching, wet etching, and electrochemical etching.

[0088] Dry etching includes, but is not limited to, any one of the following processes: inductively coupled plasma (ICP), reactive ion etching (RIE), or ion beam etching (IBE). Wet etching and electrochemical etching use etching reagents including alkaline or acidic solvents. For example, alkaline solvents include, but are limited to, any one or a combination of two or more of potassium hydroxide (KOH), sodium hydroxide (NaOH), and tetramethylammonium hydroxide (TMAH); for example, acidic solvents include, but are not limited to, any one or a combination of two of phosphoric acid (H3PO4), hydrofluoric acid (HF), and oxalic acid (HO2C–CO2H).

[0089] Surface cleaning includes, but is not limited to, the use of one or more inorganic and organic solvents. For example, inorganic solvents include, but are limited to, one or more of hydrofluoric acid (HF), phosphoric acid (H3PO4), sulfuric acid (H2SO4), and BOE (buffer oxide etch). For example, organic solvents include, but are limited to, one or more of acetone (CH3COCH3), isopropanol (C3H8O), and ethanol (C2H6O).

[0090] In step S503, a protective layer 50b is applied to the top of the retained first laser epitaxial structure 103a. This protects the completed first laser epitaxial structure 103a from further epitaxy.

[0091] In specific implementations, the protective layer 50b material includes, but is limited to, SiO2 and SiN. x (x = 0~1), any one or a combination of two or more of SiON, Al2O3, AlON, SiAlON, TiO2, and Ta2O5. Exemplarily, the thickness of the protective layer 50b is 5nm to 1000nm. It should be understood that the protective layer 50b is acceptable as long as it can protect the completed epitaxial structure from further epitaxy; this application does not limit this.

[0092] In step S504, the region of the first epitaxial structure 50a partially removed in step S502 is used to grow a second epitaxial structure 50c layer by layer, corresponding to the functional layers of the second laser epitaxial structure 103b. Here, the second epitaxial structure 50c covers the entire region of the first epitaxial structure 50a where the partial removal was made.

[0093] The selection of the growth equipment for the laser epitaxial structure can be the same as in step S501. This will not be elaborated further here.

[0094] Step S505: Remove a portion of the second epitaxial structure 50c and clean it. At the location corresponding to the third laser epitaxial structure 103c, remove a portion of the second epitaxial structure 50c, retaining the portion of the second epitaxial structure 50c corresponding to the second laser epitaxial structure 103b, and then perform surface cleaning.

[0095] Here, after removing a portion of the second epitaxial structure 50c, a structural layer close to the n-type substrate 102 can be retained for the third laser epitaxial structure 103c. For example, but not limited to, an n-type buffer layer 1031 and / or an n-type contact layer can be retained. The third laser epitaxial structure 103c is grown based on the retained n-type buffer layer 1031 and / or n-type contact layer.

[0096] In other possible implementations, a structural layer near the n-type substrate 102 may not be retained corresponding to the third laser epitaxial structure 103c, and the third laser epitaxial structure 103c may be grown based on the n-type substrate 102. The specific implementation can be chosen according to the specific process conditions, and this application embodiment does not limit the choice.

[0097] The selection of the removal process and the cleaning process can be the same as in step S502. This will not be elaborated further here.

[0098] In step S506, a protective layer 50b is applied to the top of the retained second laser epitaxial structure 103b. This protects both the completed first laser epitaxial structure 103a and the second laser epitaxial structure 103b from further epitaxial growth.

[0099] In step S507, a portion of the area of ​​the second epitaxial structure 50c, which was partially removed in step S505, is removed, and the functional layer of the third laser epitaxial structure 103c is grown layer by layer.

[0100] The selection of the growth equipment for the laser epitaxial structure can be the same as in step S501. This will not be elaborated further here.

[0101] Step S508: Remove the protective layer 50b covering the top of the first laser epitaxial structure 103a and the second laser epitaxial structure 103b.

[0102] Based on the structural pattern obtained in step S508, further steps can be performed to implement other functional structures of the laser chip. This can be achieved using existing technologies, which will not be elaborated upon here.

[0103] In the foregoing embodiments, each laser epitaxial structure 103 of the laser chip can be formed by multiple selective epitaxy to create laser epitaxial structures with different wavelengths corresponding to the same primary color in the lateral direction (first direction X). Please refer to Figure 6, which is a simplified process flow diagram of another laser epitaxial structure provided in this application embodiment.

[0104] In step S601, on the n-type substrate 102, a first epitaxial structure 60a is formed by growing the functional layers corresponding to each laser epitaxial structure layer by layer. The first epitaxial structure 60a includes the epitaxial layer up to the n-side waveguide layer 1033. Here, the first epitaxial structure 60a covers the entire surface of the n-type substrate 102.

[0105] In practice, the growth of the laser epitaxial structure can be consistent with step 501 of the aforementioned process, which will not be repeated here.

[0106] In step S602, a mask layer 60b is deposited on the first epitaxial structure 60a, corresponding to the window 60c of the laser epitaxial structure 103.

[0107] In a specific implementation, the etched mask layer 60b forms windows 60c corresponding to each laser epitaxial structure 103. This can be achieved by any method, including but not limited to dry etching, wet etching, and electrochemical etching.

[0108] Here, the material of the mask layer 60b can include, but is not limited to, SiO2 and SiN. x (x=0~1), any one or more combinations of SiON, Al2O3, AlON, SiAlON, TiO2, Ta2O5, with a thickness of 5~2000nm, a width of 10um~200um, and a window size of 10um~100um.

[0109] In step S603, within each window 60c of the mask layer 60b, the active region and remaining functional layer of each laser epitaxial structure 103 are epitaxially grown to the p-type confinement layer 1036.

[0110] Step S604: Remove mask layer 60b.

[0111] Step S605: A corresponding p-type contact layer 1037 is deposited on each p-type confinement layer 1036.

[0112] Step S606: Etch to form each waveguide 103-2.

[0113] In step S607, the trench 103-1 beside the laser epitaxial structure 103 is etched to form a mesa. In this state, the horizontally cascaded laser epitaxial structures 103 (first laser epitaxial structure 103a, second laser epitaxial structure 103b and third laser epitaxial structure 103c) are formed.

[0114] Step S608, depositing to form an insulating dielectric layer 105.

[0115] Based on the structural pattern obtained in step S608, further steps can be performed to implement other functional structures of the laser chip, such as, but not limited to, forming n-type electrode 101 and p-type electrode 104. These can be achieved using existing technologies, which will not be elaborated here.

[0116] It is understandable that the emission wavelength is mainly determined by the band gap of the active region material. In practical implementations, different wavelengths can be obtained by adjusting the 1034 band gap and stress of the active region. One implementation method is to precisely control the wavelength by adjusting the material composition (In composition) and thickness of the quantum well.

[0117] Here, the material for the multi-quantum-well structure in the active region 1034 can be a group III nitride. Specifically, the quantum well material is Al. x2 In y2 Ga (1- x2-y2) N, the material of the quantum barrier is Al x3 In y3 Ga (1-x3-y3) N, where 0≤x2≤1, 0≤y2≤1, 0≤x3≤1, 0≤y3≤1, and satisfying: 0≤(x2+y2)≤1, 0≤(x3+y3)≤1. Preferably, y2≥y3≥0.1.

[0118] In another implementation, the degree of bandgap tilt of the quantum well can be controlled by adjusting the force during the epitaxial growth process, thus obtaining the corresponding lasing wavelength based on the change in the band gap. Please refer to Figure 7, which is a schematic diagram of another laser chip architecture provided in this embodiment. To clearly illustrate the differences and connections between this embodiment and the aforementioned embodiments, identical functional components or structures are indicated by the same labels in the figure.

[0119] Compared with the laser epitaxial structures described in the foregoing embodiments, the difference in this embodiment is that the laser chip 100 further includes a mask layer 108, which is located above the n-type substrate 102. The mask layer 108 has windows 108-1 corresponding to the laser epitaxial structures 103. The three laser epitaxial structures 103 are located on the n-type substrate 102 on which the mask layer 108 is provided. Based on the mask layer 108 with windows 108-1, a portion of the n-type substrate 102 is exposed through the windows 108-1. Thus, the mechanism of epitaxial growth can be affected by the windows 108-1, achieving selected area epitaxial growth.

[0120] The mask layer 108 material may include, but is limited to, SiO2 and SiN. x (x = 0~1), any one or more combinations of SiON, Al2O3, AlON, SiAlON, TiO2, Ta2O5, ZrO2, and polycrystalline silicon. For example, the thickness of the mask layer 108 can be 5 nm to 2000 nm, and the spacing T2 between the mask layer 108 and the n-type substrate 102 in the second direction Y can be 10 nm to 3000 nm. The specific details can be determined according to the overall product design requirements, and are not limited in the embodiments of this application.

[0121] In practical implementation, adjusting the size of the windows 108-1 in the mask layer 108 improves stress control during the secondary epitaxy process, thereby modulating the bandgap or tilt of the active region quantum well to achieve wavelength change. Furthermore, the spacing between each window 108-1 is 5nm to 100um. That is, by adjusting the mask layer width and the window 108-1 size, the stress generated during the growth of the laser epitaxial structure 103 is adjusted, obtaining the corresponding lasing wavelength. It can be understood that from the perspective of stress adjustment, the longer the excitation wavelength of the laser epitaxial structure 103, the smaller the size of the window 108-1 in the mask layer. Here, a smaller mask window includes, but is not limited to, the formation of island-like growth, and the differences in growth rate and morphology of different island-like structures leading to increased local stress; additionally, it can be based on interface inhomogeneity and the introduction of more interface stress; furthermore, it can be based on increased defect density, thus increasing stress. Overall, the increase in stress leads to an increase in the bandgap / tilt of the quantum well region, thereby reducing the bandgap and achieving an increase in wavelength.

[0122] For example, for three laser epitaxial structures 103 with different lasing wavelengths, the window 108-1 of the corresponding mask layer 108 has different sizes, which can correspond to the wavelengths of the three primary colors of RGB respectively. The wavelength of the third laser epitaxial structure 103c is 600nm~700nm, the wavelength of the second laser epitaxial structure 103b is 500nm~570nm, and the wavelength of the first laser epitaxial structure 103a is 400nm~470nm.

[0123] For example, for three laser epitaxial structures 103 with the same lasing wavelength, the window 108-1 of the corresponding mask layer 108 has the same size. Furthermore, when the lasing wavelengths of each laser epitaxial structure 103 correspond to different wavelengths of the same primary color, the wavelength spacing does not exceed 10 nm, which can achieve better scattering effect.

[0124] To prevent the dislocation extension of the lower epitaxial structure from affecting the performance and reliability of the laser, the geometric center line of the window 108-1 in the second direction Y is offset from the geometric center line of the waveguide 103-2 of the laser epitaxial structure 103.

[0125] In a specific implementation, the laser epitaxial structure 103 above the mask layer 108 can be achieved through secondary epitaxial growth, and the dislocation density in the upper laser functional layer can be reduced through dislocation bending, annihilation, and other methods. Please refer to Figure 8, which is a simplified process flow diagram of another laser epitaxial structure provided in an embodiment of this application.

[0126] As shown in Figure 8, the process steps of secondary epitaxial growth are illustrated by the three laser epitaxial structures 103 shown in Figure 7.

[0127] In step S701, a bottom layer structure 70a of each laser epitaxial structure 103 is grown on an n-type substrate 102; then, a mask layer 108 is deposited on the bottom layer structure 70a.

[0128] In practice, the growth of laser epitaxial structures can be achieved using one of the following methods: metal-organic chemical vapor deposition (MOCVD), atmospheric pressure chemical vapor deposition (APCVD), or molecular beam epitaxy (MBE).

[0129] Step S702: Etch mask layer 108 to form windows 108-1 corresponding to each laser epitaxial structure 103.

[0130] In practice, any material removal process, such as dry etching, wet etching, or electrochemical etching, can be used to form each window 108-1.

[0131] Step S703: Epitaxial growth is performed to form functional layers of each laser epitaxial structure (first laser epitaxial structure 103a, second laser epitaxial structure 103b and third laser epitaxial structure 103c).

[0132] The selection of the growth equipment for the laser epitaxial structure can be the same as in step S701. This will not be elaborated further here.

[0133] Based on the structural pattern obtained in step S703, the processes for implementing other functional structures of the laser chip can be further executed. This can be achieved using existing technologies, which will not be elaborated upon here.

[0134] Based on the aforementioned laser chip, this application embodiment also provides a laser module. Please refer to Figure 9, which is a schematic diagram of the assembly relationship of the laser module provided in this application embodiment.

[0135] The laser module 1000a includes a laser chip 100 as described above, a circuit board 200, a housing 300, a reflector 400, a sapphire cover plate 500, and a collimating lens array 600. As shown in Figure 9, the laser chip 100 can be encapsulated within the housing 300 mounted on the circuit board 200. The circuit board 200 can provide the laser chip 100 with stable current drive, modulation signals, and temperature control to generate laser light. A reflector is disposed within the housing 300 to adjust the beam propagation direction of the laser. The sapphire cover plate 500 is sealed to the housing 300 to form a hermetically sealed device. The collimating lens array 600 is stacked on the sapphire cover plate 500 to ensure beam quality.

[0136] Based on the aforementioned laser chip, this laser module also has the ability to reduce cost and size, effectively improve speckle in projection scenarios, and avoid problems such as reduced light efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate that may result from increasing power by increasing operating current.

[0137] It should be understood that the other functional components of the laser module 1000a can be implemented using existing technologies. These will not be elaborated upon here.

[0138] Based on the aforementioned laser chip, this application also provides an optical module. Please refer to Figure 10, which is a schematic diagram of the optical module provided in this application embodiment.

[0139] The optical module 1000b includes a driver chip 200b and a laser chip 100 as described in Figures 1, 3, 4 or 7 above. The output terminal of the driver chip 200b is electrically connected to the laser chip 100. The driver chip 200b is used to inject electrons into the electrode layer of the laser chip 100.

[0140] In a specific implementation, the driver chip 200b and the laser chip 100 are mounted on the same substrate (not shown in the figure). In other implementations, the driver chip 200b and the laser chip 100 are packaged separately; for example, the driver chip is packaged in a driver module, and the laser chip is packaged in a laser device. Based on the aforementioned laser chip, this optical module also has the advantages of reducing cost and size, effectively improving speckle in the projection scene, and avoiding the problems of reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate that may result from increasing power by increasing operating current.

[0141] Based on the aforementioned optical module, this application embodiment also provides a laser device, which includes an optical component and the optical module described in FIG10. The optical component is used to adjust the optical parameters (not shown in the figure) of the laser output by the optical module. The optical parameters of the laser include, but are not limited to, at least one of the following: laser propagation direction, spot size, polarization state, intensity, and wavelength. For example, but not limited to, the optical component includes a collimating lens used to collimate the incident laser before output. Based on the aforementioned laser chip, this optical module also has the advantages of reducing cost and size, effectively improving speckle in the projection scene, and avoiding the problems of reduced luminous efficiency, increased heat dissipation, decreased efficiency, and excessively large substrate that may result from increasing power by increasing operating current.

[0142] It should be understood that other functional components of this laser device can be implemented using existing technologies. These will not be elaborated upon here.

[0143] Furthermore, the ordinal numbers "first" and "second," etc., used herein are only for describing the composition or structure of the same function in the technical solution. It is understood that the use of the aforementioned ordinal numbers does not constitute a limitation on the understanding of the technical solution for which protection is sought in this application.

[0144] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A laser chip, characterized in that, The laser chip includes an n-type electrode, a substrate, a laser epitaxial structure, and a p-type electrode. The laser epitaxial structure is configured to be at least two, and the at least two laser epitaxial structures are cascaded sequentially on the substrate in a first direction, where the first direction is a direction within the plane of the substrate. Of the n-type electrode and the p-type electrode, one is located on the side of the substrate away from the laser epitaxial structure in the second direction, and the other is located on the side of the laser epitaxial structure away from the substrate in the second direction; the second direction is the direction intersecting with the plane where the substrate is located.

2. The laser chip according to claim 1, characterized in that, At least two of the laser epitaxial structures have the same or different lasing wavelengths.

3. The laser chip according to claim 1 or 2, characterized in that, The laser epitaxial structure is configured as three, namely a first laser epitaxial structure, a second laser epitaxial structure and a third laser epitaxial structure; the lasing wavelength of the third laser epitaxial structure is 600nm to 700nm, the lasing wavelength of the second laser epitaxial structure is 500nm to 570nm, and the lasing wavelength of the first laser epitaxial structure is 400nm to 470nm.

4. The laser chip according to claim 1 or 2, characterized in that, The lasing wavelengths of each of the laser epitaxial structures correspond to the same primary color, and the lasing wavelength spacing between each of the laser epitaxial structures is no greater than 10 nm.

5. The laser chip according to any one of claims 1 to 4, characterized in that, The substrate and the epitaxial structure of the laser are made of group III nitrides.

6. The laser chip according to any one of claims 1 or 5, characterized in that, The substrate is an n-type substrate, the n-type electrode is electrically connected to the n-type substrate, and the laser epitaxial structure includes, in sequence along the second direction, an n-type buffer layer, an n-type confinement layer, an n-side waveguide layer, an active region, a p-side waveguide layer, a p-type confinement layer, and a p-type contact layer; the p-type electrode is electrically connected to the surface of the p-type contact layer away from the p-type confinement layer.

7. The laser chip according to claim 6, characterized in that, The p-type electrode is configured to be at least two, and the p-type electrode is configured to correspond one-to-one with the p-type contact layer.

8. The laser chip according to claim 6, characterized in that, At least two of the p-type contact layers of the laser epitaxial structure are electrically connected to the same p-type electrode.

9. The laser chip according to any one of claims 6 to 8, characterized in that, The active region includes one or more quantum well structures, and the quantum well material of the quantum well structure is Al. x2 In y2 Ga (1-x2-y2) N, the material of the quantum barrier is Al x3 In y3 Ga (1-x3-y3) N, where 0≤x2≤1, 0≤y2≤1, 0≤x3≤1, 0≤y3≤1, 0≤(x2+y2)≤1, 0≤(x3+y3)≤1.

10. The laser chip according to claim 9, characterized in that, y2≥y3≥0.

1.

11. The laser chip according to any one of claims 6 to 10, characterized in that, The material of the n-type confinement layer, the n-side waveguide layer, the active region, the p-side waveguide layer, the p-type confinement layer, and / or the p-type contact layer is Al. x1 In y1 Ga (1-x1-y1) N, where 0≤x1≤1, 0≤y2≤1, and 0≤(x1+y1)≤1.

12. The laser chip according to any one of claims 6 to 11, characterized in that, A trench is formed between two adjacent laser epitaxial structures, and an insulating dielectric layer is filled in the trench. The dimensions of the trench are configured as follows: width of 1µm to 100µm, length of 100µm to 2000µm, and depth of 1µm to 10µm.

13. The laser chip according to claim 12, characterized in that, The n-type buffer layers of two adjacent laser epitaxial structures are interconnected.

14. The laser chip according to any one of claims 1 to 13, characterized in that, The laser chip further includes a mask layer located above the substrate. The mask layer has windows corresponding to each of the laser epitaxial structures, and each of the laser epitaxial structures is located on the substrate on which the mask layer is disposed.

15. The laser chip according to claim 14, characterized in that, In the second direction, the geometric center line of the window is offset from the geometric center line of the waveguide of the corresponding laser epitaxial structure.

16. A laser module, characterized in that, The laser module includes a laser chip, a circuit board, a reflector, and a housing. The laser chip is the laser chip according to any one of claims 1 to 15. The housing is disposed on the circuit board, and the compatible laser chip and the reflector are located inside the housing.

17. An optical module, characterized in that, The optical module includes a driver chip and a laser chip, wherein the laser chip is the laser chip according to any one of claims 1 to 15, and the output terminal of the driver chip is electrically connected to the laser chip.

18. A laser device, characterized in that, The laser device includes optical components and an optical module, wherein the optical module is the optical module described in claim 17, and the optical components are used to adjust the optical parameters of the laser output by the optical module.

19. A method for fabricating a laser chip, characterized in that, The laser chip includes at least two laser epitaxial structures, which are cascaded sequentially on the substrate in a first direction, wherein the first direction is a direction within the plane of the substrate; the fabrication method includes the following steps: On the substrate, at least two laser epitaxial structures are formed by multiple selective region epitaxial growths.

20. The method for fabricating a laser chip according to claim 19, characterized in that, The multiple selective region epitaxial growths forming the at least two laser epitaxial structures include: A first epitaxial structure is formed by growing one layer of the epitaxial structure corresponding to one of the lasers, and the first epitaxial structure covers the entire surface of the substrate; A portion of the first epitaxial structure is removed to form a retained region corresponding to one of the laser epitaxial structures; A protective layer is placed on top of the reserved area; For the other laser epitaxial structures in the at least two laser epitaxial structures, the corresponding epitaxial structures are grown layer by layer again until the growth of the complete laser epitaxial structure is achieved. Remove the protective layer.

21. The method for fabricating a laser chip according to claim 19, characterized in that, The multiple selective region epitaxial growths forming the at least two laser epitaxial structures include: The underlying structure of each laser epitaxial structure is grown; The mask layer is etched to form windows corresponding to the epitaxial structures of each laser; The functional layers of each laser epitaxial structure are formed by epitaxial growth.

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