Vertical cavity surface emitting laser and preparation method thereof
阅读说明：本技术 一种垂直腔面发射激光器及其制备方法 (Vertical cavity surface emitting laser and preparation method thereof ) 是由 杨翠柏 于 2021-08-26 设计创作，主要内容包括：本发明提供了一种电流自供给硅基垂直腔面发射激光器,其结构包括Si衬底,激光器单元、隔离区和太阳电池单元。Si衬底为p型Si单晶片；激光器单元在Si衬底的上表面按照层状叠加结构从下至上依次设置有缓冲层、反射层、多量子阱激光发射单元、反射层和电极接触层,在电极接触层正上方制备有上电极,在Si衬底下表面制备有下电极；隔离区为高电阻区域；太阳电池单元从下至上包括Si衬底、n型发射区和窗口层,在n型发射区上方制备有上电极,在Si衬底下表面制备有下电极。本发明在降低材料制作成本的同时还可以实现VCSEL系统的电流自供给,大大降低了VCSEL系统的工作能耗。(The invention provides a silicon-based vertical cavity surface emitting laser with self-supplied current, which structurally comprises a Si substrate, a laser unit, an isolation region and a solar cell unit. The Si substrate is a p-type Si single chip; the laser unit is sequentially provided with a buffer layer, a reflecting layer, a multi-quantum well laser emission unit, the reflecting layer and an electrode contact layer from bottom to top on the upper surface of a Si substrate according to a layered superposed structure, an upper electrode is prepared right above the electrode contact layer, and a lower electrode is prepared on the lower surface of the Si substrate; the isolation region is a high-resistance region; the solar cell unit comprises a Si substrate, an n-type emitting region and a window layer from bottom to top, wherein an upper electrode is prepared above the n-type emitting region, and a lower electrode is prepared on the lower surface of the Si substrate. The invention can realize the current self-supply of the VCSEL system while reducing the material manufacturing cost, thereby greatly reducing the working energy consumption of the VCSEL system.)
1. A current self-feeding silicon-based vertical cavity surface emitting laser, comprising a laser unit, a high resistance isolation region and a solar cell unit, wherein the laser unit and the solar cell unit share a Si substrate, and the laser unit and the solar cell unit are separated by the isolation region;
in the laser unit, the upper surface of a Si substrate sequentially comprises a buffer layer, a first reflecting layer, a GaNP/GaNAsP/GaNP multi-quantum well laser emitting unit, a second reflecting layer, an electrode contact layer and an upper electrode, and the lower surface of the Si substrate is provided with a lower electrode;
in the solar cell unit, an n-type emitter region and a window layer are sequentially arranged on the upper surface of a Si substrate, an upper electrode is arranged above the n-type emitter region, and a lower electrode is arranged on the lower surface of the Si substrate;
the upper electrode of the laser unit is connected with the upper electrode of the solar cell unit, and the lower electrode of the laser unit is connected with the lower electrode of the solar cell unit.
2. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 1, wherein: the Si substrate is a p-type single crystal Si substrate, the buffer layer is a p-type GaNP buffer layer, the first reflecting layer is a p-type DBR reflecting layer, the second reflecting layer is an n-type DBR reflecting layer, and the electrode contact layer is an n-type GaNP electrode contact layer.
3. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 2, wherein: all material lattice constants of a p-type GaNP buffer layer, a p-type DBR reflecting layer, a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit, an n-type DBR reflecting layer and an n-type GaNP electrode contact layer of the laser unit are kept the same as that of the Si substrate.
4. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 2, wherein: the thickness of the p-type GaNP buffer layer of the laser unit is 200-800 nm.
5. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 2, wherein: the p-type DBR reflecting layer of the laser unit consists of p-type doped GaNP/AlNP, and the number of pairs of GaNP/AlNP is 30-50.
6. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 1, wherein: the optical band gap of an active region material GaNAsP in a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit of the laser unit is 1.3-1.6 eV, and the number of quantum wells is 2-5.
7. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 2, wherein: the n-type DBR reflecting layer of the laser unit consists of n-type doped GaNP/AlNP, and the number of pairs of GaNP/AlNP is 20-40; an oxide confinement layer is also provided between the n-type DBR reflective layer and the multiple quantum well laser emitting unit.
8. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 2, wherein: the doping concentration of the n-type GaNP electrode contact layer of the laser unit is more than 5 x 1018cm-3。
9. A current self-powered silicon-based vertical cavity surface emitting laser according to claim 1, wherein: the doping concentration of the n-type emitter region of the solar cell unit is 1 multiplied by 1018～1×1019cm-3The thickness is 100 to 500 nm.
10. A current self-feeding silicon-based straight cavity surface emitting laser according to claim 1, wherein: the window layer of the solar cell unit is made of silicon nitride with wide band gap and light transmission, and the thickness of the window layer is 20-50 nm.
11. A method for preparing a silicon-based vertical cavity surface emitting laser with self-supplied current is characterized by comprising the following steps:
step S1: providing p-type single crystal Si as a Si substrate, wherein the Si substrate comprises a laser unit region and a solar cell region, and an isolation region between the laser unit region and the solar cell region, and then growing a buffer layer on the upper surface of the laser unit region of the Si substrate;
step S2: growing a first reflective layer on the buffer layer;
step S3: growing a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit on the first reflecting layer;
step S4: growing a second reflecting layer on the multiple quantum well laser emission unit;
step S5: growing an electrode contact layer on the second reflective layer;
step S6: forming an oxidation limiting layer of the laser unit on the stacked structure manufactured in the steps S1-S5 by adopting photoetching and wet oxidation processes, wherein the oxidation limiting layer is positioned between the n-type DBR reflecting layer and the multi-quantum well laser emitting unit;
step S7: forming a high-resistance isolation region on the isolation region of the Si substrate by adopting photoetching and ion implantation processes;
step S8: forming an n-type emitter region of the solar cell unit on the surface of the solar cell unit region of the Si substrate by adopting photoetching and ion implantation processes;
step S9: forming a silicon nitride window layer on the surface of the n-type emitter region;
step S10: fabricating an upper electrode on the stacked structure completing the step S9;
step S11: and manufacturing a lower electrode on the lower surface of the Si substrate.
12. The method of claim 11, wherein the step of forming a self-current-supplying silicon-based surface-emitting laser comprises: the buffer layer is a p-type GaNP buffer layer, the first reflecting layer is a p-type DBR reflecting layer, the second reflecting layer is an n-type DBR reflecting layer, and the electrode contact layer is an n-type GaNP electrode contact layer.
Technical Field
The invention relates to the technical field of semiconductor lasers, in particular to a vertical cavity surface emitting laser and a preparation method thereof, and more particularly relates to a silicon-based vertical cavity surface emitting laser with self-supplied current and a preparation method thereof.
Background
In recent years, with the market demand of 5G communication, smart phones and smart manufacturing expanding, the application of semiconductor Vertical Cavity Surface Emitting Lasers (VCSELs) in the fields of optical communication, 3D sensing, industrial detection and the like is more and more extensive. The VCSEL with the lasing wavelength of 750-800 nm can be applied to various sensing systems in the fields of industry, medical treatment and the like, the VCSEL with the wavelength of 850nm can be applied to a short-range optical fiber communication system, and the VCSEL with the wavelength of 940-980 nm can be applied to systems such as 3D sensing and particle generators.
While VCSEL arrays have limited specific applications in outdoor probing sensing or communication systems due to power consumption and power supply aspects of the system.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings of the prior art and provides a silicon-based vertical cavity surface emitting laser with self-supplied current, wherein a GaNAsP material matched with crystalline silicon is used as an active layer, and a VCSEL with the lasing wavelength in the range of 780-950 nm can be prepared on the basis of a crystalline silicon substrate; meanwhile, the silicon substrate is integrated with the VCSEL during the preparation of the solar cell, so that the silicon-based VCSEL can be self-supplied with current. Compared with a GaAs-based VCSEL, the technology is used for preparing the VCSEL device with adjustable lasing wavelength directly based on the monocrystalline silicon wafer, so that the material cost is reduced, the integration with a solar cell is realized, the current self-supply function of a VCSEL array is realized, and the system power consumption of the VCSEL can be greatly reduced.
The technical scheme provided by the invention is as follows:
a current self-feeding silicon-based vertical cavity surface emitting laser, comprising a laser unit, a high resistance isolation region and a solar cell unit, wherein the laser unit and the solar cell unit share a Si substrate, and the laser unit and the solar cell unit are separated by the isolation region;
in the laser unit, the upper surface of a Si substrate sequentially comprises a buffer layer, a first reflecting layer, a GaNP/GaNAsP/GaNP multi-quantum well laser emitting unit, a second reflecting layer, an electrode contact layer and an upper electrode, and the lower surface of the Si substrate is provided with a lower electrode;
in the solar cell unit, an n-type emitter region and a window layer are sequentially arranged on the upper surface of a Si substrate, an upper electrode is arranged above the n-type emitter region, and a lower electrode is arranged on the lower surface of the Si substrate;
the upper electrode of the laser unit is connected with the upper electrode of the solar cell unit, and the lower electrode of the laser unit is connected with the lower electrode of the solar cell unit.
Further, the Si substrate is a p-type single crystal Si substrate, the buffer layer is a p-type gan buffer layer, the first reflective layer is a p-type DBR reflective layer, the second reflective layer is an n-type DBR reflective layer, and the electrode contact layer is an n-type gan electrode contact layer.
Further, all material lattice constants of the p-type GaNP buffer layer, the p-type DBR reflection layer, the GaNP/GaNAsP/GaNP multi-quantum well laser emission unit, the n-type DBR reflection layer and the n-type GaNP electrode contact layer of the laser unit are kept the same as the Si substrate.
Furthermore, the thickness of the p-type GaNP buffer layer of the laser unit is 200-800 nm.
Furthermore, the p-type DBR reflecting layer of the laser unit is composed of p-type doped GaNP/AlNP, and the number of pairs of GaNP/AlNP is 30-50.
Furthermore, the optical band gap of an active region material GaNAsP in the GaNP/GaNAsP/GaNP multi-quantum well laser emission unit of the laser unit is 1.3-1.6 eV, and the number of quantum wells is 2-5.
Furthermore, the n-type DBR reflecting layer of the laser unit consists of n-type doped GaNP/AlNP, and the number of pairs of GaNP/AlNP is 20-40; an oxide confinement layer is also provided between the n-type DBR reflective layer and the multiple quantum well laser emitting unit.
Further, the doping concentration of the n-type GaNP electrode contact layer of the laser unit is more than 5 x 1018cm-3。
Further, the doping concentration of the n-type emitting region of the solar cell unit is 1 multiplied by 1018～1×1019cm-3The thickness is 100 to 500 nm.
Furthermore, the window layer of the solar cell unit is made of silicon nitride with wide band gap and light transmission, and the thickness of the window layer is 20-50 nm.
The invention also relates to a preparation method of the silicon-based vertical cavity surface emitting laser with self-supplied current, which comprises the following steps:
step S1: providing p-type single crystal Si as a Si substrate, wherein the Si substrate comprises a laser unit region and a solar cell region, and an isolation region between the laser unit region and the solar cell region, and then growing a buffer layer on the upper surface of the laser unit region of the Si substrate;
step S2: growing a first reflective layer on the buffer layer;
step S3: growing a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit on the first reflecting layer;
step S4: growing a second reflecting layer on the multiple quantum well laser emission unit;
step S5: growing an electrode contact layer on the second reflective layer;
step S6: forming an oxidation limiting layer of the laser unit on the stacked structure manufactured in the steps S1-S5 by adopting photoetching and wet oxidation processes, wherein the oxidation limiting layer is positioned between the n-type DBR reflecting layer and the multi-quantum well laser emitting unit;
step S7: forming a high-resistance area on the isolation area of the Si substrate by adopting photoetching and ion implantation processes;
step S8: forming an n-type emitter region of the solar cell unit on the surface of the solar cell unit region of the Si substrate by adopting photoetching and ion implantation processes;
step S9: forming a silicon nitride window layer on the surface of the n-type emitter region;
step S10: fabricating an upper electrode on the stacked structure completing the step S9;
step S11: and manufacturing a lower electrode on the lower surface of the Si substrate.
Further, the buffer layer is a p-type GaNP buffer layer, the first reflecting layer is a p-type DBR reflecting layer, the second reflecting layer is an n-type DBR reflecting layer, and the electrode contact layer is an n-type GaNP electrode contact layer.
According to the vertical cavity surface emitting laser structure formed by the invention, a laser unit, an isolation region and a solar cell unit are arranged on a Si substrate by utilizing a single crystal Si substrate and combining the self characteristics of nitride materials such as GaNAsP and the like; the upper electrode of the laser unit is connected with the upper electrode of the solar cell unit, the lower electrode of the laser unit is connected with the lower electrode of the solar cell unit, and finally the silicon-based vertical cavity surface emitting laser integrated with the solar cell can be obtained, current self-supply can be realized under the illumination condition, and the material manufacturing cost is reduced. The silicon-based vertical cavity surface emitting laser can adjust the laser emission wavelength by utilizing the band gap characteristic of a GaNAsP material, and is conveniently applied to the fields of industrial detection, optical communication, 3D sensing and the like; meanwhile, the current self-supply of the VCSEL system can be realized by combining the characteristics of the crystalline silicon solar cell, and the energy consumption of the VCSEL system during working is greatly reduced. In a word, the invention can manufacture the vertical cavity surface emitting laser with self-supplied current based on the crystalline silicon substrate and has stronger application value.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic diagram of a unit cell of a current self-supplying silicon-based VCSEL device.
FIG. 2 is a schematic view of an epitaxial structure of a current self-powered silicon-based VCSEL.
FIG. 3 is a flow chart of a process for fabricating a unit structure of a self-current-supplying silicon-based VCSEL device.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
Referring to fig. 1-2, fig. 1 is a schematic structural diagram of a unit of a current self-supply silicon-based vertical cavity surface emitting laser device provided in an embodiment of the present application, fig. 2 is a schematic structural diagram of an epitaxial structure of a current self-supply silicon-based vertical cavity surface emitting laser, and it can be known from the structural diagrams shown in fig. 1-2 that:
an epitaxial structure for forming a vertical cavity surface emitting laser is sequentially laminated from bottom to top into a p-type single crystal Si substrate 1, a p-type GaNP buffer layer 2, a p-type DBR reflection layer 3, a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit 4, an n-type DBR reflection layer 5 and an n-type GaNP electrode contact layer 6.
Referring to fig. 1, the self-current-supplying silicon-based vertical cavity surface emitting laser provided by the present invention includes a laser unit, a high resistance isolation region and a solar cell unit, wherein the laser unit and the solar cell unit share a Si substrate, and the laser unit and the solar cell unit are separated by the isolation region;
the laser unit includes: the upper surface of the Si substrate 1 sequentially comprises a buffer layer, a first reflecting layer, a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit 4, a second reflecting layer, an electrode contact layer and an upper electrode, and the lower surface of the Si substrate is provided with a lower electrode;
the Si substrate is a p-type single crystal Si substrate 1, the buffer layer is a p-type GaNP buffer layer 2, and the thickness of the p-type GaNP buffer layer of the laser unit is 200-800 nm; the first reflecting layer is a p-type DBR (distributed Bragg reflector) reflecting layer 3, the p-type DBR reflecting layer of the laser unit is composed of p-type doped GaNP/AlNP, the number of pairs of GaNP/AlNP is 30-50, and Bragg reflection of light can be better improved;
the optical band gap of an active region material GaNAsP in a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit of the laser unit is 1.3-1.6 eV, the number of quantum wells is 2-5, and in a Si substrate-based vertical cavity surface laser, the GaNAsP material is used as the active region material, so that lattice matching can be better performed with a single crystal Si substrate, and the manufacturing cost of a VCSEL (vertical cavity surface emitting laser) can be reduced.
The second reflecting layer is an n-type DBR reflecting layer 5, the n-type DBR reflecting layer of the laser unit is composed of n-type doped GaNP/AlNP, and the number of pairs of GaNP/AlNP is 20-40; an oxidation confinement layer 5-1 is further provided between the n-type DBR reflection layer and the multiple quantum well laser emission unit, and the oxidation confinement layer 5-1 of the laser unit is located at the lowermost part of the n-type DBR reflection layer 5 and the cross-sectional area of the oxidation confinement layer 5-1 is smaller than the cross-sectional area of the n-type DBR reflection layer 5.
The electrode contact layer is an n-type GaNP electrode contact layer 6, and the doping concentration of the n-type GaNP electrode contact layer of the laser unit is more than 5 x 1018cm-3The contact resistance can be reduced.
And all the material lattice constants of the p-type GaNP buffer layer, the p-type DBR reflecting layer, the GaNP/GaNAsP/GaNP multi-quantum well laser emission unit, the n-type DBR reflecting layer and the n-type GaNP electrode contact layer of the laser unit are kept the same as the Si substrate, so that a lattice-matched multilayer structure can be formed on the Si substrate better, and the performance of the laser structure is improved.
The upper electrode 9 of the laser unit is positioned right above the n-type GaNP electrode contact layer 6, and the lower electrode 10 is positioned right below the p-type single crystal Si substrate 1.
On the single crystal Si substrate, an isolation region is arranged between the laser unit and the solar cell unit, and the isolation region is a high-resistance isolation region formed by ion implantation, so that electron transmission and current conduction at two sides can be prevented.
In the solar cell unit, an n-type emitter region 7 and a window layer 8 are sequentially arranged on the upper surface of a Si substrate, an upper electrode 9 is arranged above the n-type emitter region, and a lower electrode 10 is arranged on the lower surface of the Si substrate; the doping concentration of the n-type emitter region of the solar cell unit is 1 multiplied by 1018～1×1019cm-3The thickness is 100 to 500 nm.
The window layer of the solar cell unit is made of silicon nitride with wide band gap and light transmission, the thickness of the window layer is 20-50 nm, the window layer 8 is formed through the processes of photoetching, PECVD coating and the like, the window layer 8 has good insulation and light transmission, ambient light can be determined to enter from the window layer, and the edge of the side face of the laser can be insulated.
The upper electrode 9 of the solar cell unit is directly contacted with the n-type emitter region through a photoetching process, and the lower electrode 10 is positioned right below the p-type monocrystalline Si substrate 1.
An upper electrode 9 and a lower electrode 10 are formed through processes such as photoetching, metal evaporation and the like, the upper electrode of the laser unit is connected with the upper electrode of the solar cell unit (both are the upper electrode layers 9), and the lower electrode of the laser unit is connected with the lower electrode of the solar cell unit (both are the lower electrode layers 10), so that when external light irradiates the solar cell unit, the solar cell unit can generate electromotive force through a photovoltaic effect, power supply is carried out on the vertical laser unit, current self-supply is realized, and energy consumption of a VCSEL system during working can be reduced.
In the embodiment of the application, the epitaxial material of the silicon-based vertical cavity surface emitting laser is subjected to flow sheet processing such as photoetching, oxidation, ion implantation, film coating, metal evaporation and the like to form an oxidation limiting layer and an isolation region of a laser unit, an n-type emitting region and a window layer of a solar cell unit, and an upper electrode and a lower electrode.
Referring to fig. 3, a specific process for fabricating the above-mentioned current self-supplying silicon-based vcsel in this embodiment includes the following steps:
step S1: providing p-type single crystal Si as a Si substrate, wherein the Si substrate comprises a laser unit region and a solar cell region, and an isolation region between the laser unit region and the solar cell region, and then growing a buffer layer on the upper surface of the laser unit region of the Si substrate;
in a specific embodiment, a 4-inch p-type single crystal Si wafer can be selected as a substrate (not limited to a 4-inch single crystal Si wafer), and a p-type gan buffer layer is grown on the upper surface of the Si substrate by using a metal organic chemical vapor deposition technique or a molecular beam epitaxy technique, wherein the thickness of the p-type gan buffer layer is 200-800 nm, and preferably 300 nm;
step S2: growing a first reflective layer on the buffer layer;
growing a p-type DBR (distributed Bragg reflector) layer on the p-type GaNP buffer layer by adopting a metal organic chemical vapor deposition technology or a molecular beam epitaxy technology, wherein the p-type DBR layer consists of p-type doped GaNP/AlNP, the number of pairs of GaNP/AlNP is 30-50, the Bragg reflection of light can be better improved, and the number of pairs of GaNP/AlNP is preferably 40;
step S3: growing a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit on the first reflecting layer;
the method comprises the steps of growing GaNP/GaNAsP/GaNP multi-quantum well laser emission units on a p-type DBR reflecting layer by adopting a metal organic chemical vapor deposition technology or a molecular beam epitaxy technology, wherein the optical band gap of active region material GaNAsP is 1.3-1.6 eV, the number of quantum wells is 2-5, and in a vertical cavity surface laser based on a Si substrate, the GaNAsP material is used as the active region material, so that lattice matching can be better performed with a single crystal Si substrate, and the manufacturing cost of the VCSEL can be reduced. Preferably, the optical band gap of the GaNAsP is 1.46eV, and the number of quantum wells is 3;
step S4: growing a second reflecting layer on the multiple quantum well laser emission unit;
growing an n-type DBR reflecting layer on a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit by adopting a metal organic chemical vapor deposition technology or a molecular beam epitaxy technology, wherein the n-type DBR reflecting layer consists of n-type doped GaNP/AlNP, the number of pairs of GaNP/AlNP is 20-40, and the number of pairs of GaNP/AlNP is preferably 30;
step S5: growing an electrode contact layer on the second reflective layer;
growing n-type GaNP electrode contact layer on n-type DBR reflecting layer by metal organic chemical vapor deposition or molecular beam epitaxy18cm-3The preferred doping concentration is 1X 1019cm-3The contact resistance can be reduced.
Step S6: and forming an oxidation limiting layer of the laser unit on the stacked structure manufactured in the step S1-S5 by adopting photoetching and wet oxidation processes, wherein the oxidation limiting layer is positioned between the n-type DBR reflecting layer and the multi-quantum well laser emitting unit, the oxidation limiting layer is positioned at the lowest part of the n-type DBR reflecting layer, and the cross-sectional area of the oxidation limiting layer 5-1 is smaller than that of the n-type DBR reflecting layer 5. Specifically, a photoresist may be used to cover and protect the region that does not need to be oxidized, so as to expose the lower portion of the n-type DBR reflective layer, and then a wet oxidation process is used to wet oxidize the bottom portion of the n-type DBR reflective layer, thereby forming the oxidation limiting layer 5-1.
Step S7: forming a high-resistance area on the isolation area of the Si substrate by adopting photoetching and ion implantation processes; specifically, a photoresist layer may be coated on the surface of the entire structure, and then the photoresist layer is exposed and developed to expose the isolation region, and then ions are implanted using non-conductive ions, for example, Ar ions or N ions, to form a high-resistance isolation region, which can prevent electron transfer and current conduction at both sides of the laser region and the solar cell region.
Step S8: forming an n-type emitter region of the solar cell unit on the surface of the solar cell unit region of the Si substrate by adopting photoetching and ion implantation processes;
removing the photoresist layer after forming the high-resistance isolation region in step S7, forming an n-type emitter region of the solar cell unit on the formed material sheet by photolithography and ion implantation, implanting n-type ions into the monocrystalline Si substrate of the solar cell region, wherein the doping concentration of the n-type emitter region is 1 × 1018～1×1019cm-3The thickness is 100-500 nm, and the preferred doping concentration of the n-type emitter region is 5 multiplied by 1018cm-3And the thickness is 200 nm.
Step S9: forming a silicon nitride window layer on the surface of the n-type emitter region;
forming a silicon nitride window layer on the material sheet formed in the step S8 by adopting photoetching and coating processes, wherein the thickness of the window layer is 20-50 nm, specifically, a silicon nitride layer can be deposited by PECVD (plasma enhanced chemical vapor deposition) coating and other processes, and then photoetching and etching are carried out to form a window layer 8, wherein the window layer 8 has good insulation and light transmission, can determine that ambient light enters from the window layer, and can play an insulation role in the edge of the side surface of the laser; the preferred window layer thickness is 30 nm. An opening is then formed in the window layer 8 to expose the n-type emitter region 7, via etching.
Step S10: fabricating an upper electrode on the stacked structure completing the step S9;
manufacturing upper electrodes above the laser unit and the solar cell unit on the material sheet formed in the step S9 by adopting photoetching and metal evaporation processes; the upper electrode 9 extends from the n-type emitter region of the solar cell to the electrode contact layer 6 of the laser unit, and the upper electrode of the solar cell and the upper electrode of the laser unit are connected to each other. The electrode is made of metal such as Au, Ag or Pt.
Step S11: and manufacturing a lower electrode on the lower surface of the Si substrate.
And (4) manufacturing a lower electrode on the lower surface of the Si substrate on the material sheet formed in the step (S10) by adopting photoetching and metal evaporation processes, and connecting the lower electrode of the solar cell unit and the lower electrode of the laser unit. The lower electrode is made of metal such as Au, Ag or Pt.
In summary, the present invention utilizes a single crystal Si substrate, and combines the characteristics of nitride materials such as GaNAsP, etc., to provide a laser unit, an isolation region, and a solar cell unit on the Si substrate. The laser unit is sequentially provided with a p-type GaNP buffer layer, a p-type DBR reflecting layer, a GaNP/GaNAsP/GaNP multi-quantum well laser emission unit, an n-type DBR reflecting layer and an n-type GaNP electrode contact layer from bottom to top, an upper electrode is prepared right above the n-type GaNP electrode contact layer, and a lower electrode is prepared on the lower surface of a Si substrate; the isolation region is a high-resistance region and prevents the conduction of current; the solar cell unit comprises a Si substrate, an n-type emitting region and a window layer from bottom to top, wherein an upper electrode is prepared right above the window layer, and a lower electrode is prepared on the lower surface of the Si substrate. Finally, the silicon-based vertical cavity surface emitting laser integrated with the solar cell can be obtained, the current self-supply can be realized under the illumination condition, and the material manufacturing cost is reduced. The silicon-based vertical cavity surface emitting laser can adjust the laser emission wavelength by utilizing the band gap characteristic of a GaNAsP material, and is conveniently applied to the fields of industrial detection, optical communication, 3D sensing and the like; meanwhile, the current self-supply of the VCSEL system can be realized by combining the characteristics of the crystalline silicon solar cell, and the energy consumption of the VCSEL system during working is greatly reduced. In a word, the invention can manufacture the vertical cavity surface emitting laser with self-supplied current based on the crystalline silicon substrate, has stronger application value and is worthy of popularization.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.