阅读说明：本技术 基于柔性衬底的半导体外延结构、vcsel及制作方法 (Semiconductor epitaxial structure based on flexible substrate, VCSEL and manufacturing method ) 是由 李峰柱 田宇 刘潇杰 韩效亚 杜石磊 于 2019-10-24 设计创作，主要内容包括：本发明提供一种基于柔性衬底的半导体外延结构、VCSEL及制作方法,采用氟金云母作为衬底,既解决了现有半导体衬底不可弯折、不易剥离的问题,又兼顾了半导体器件的温度要求。对于缓冲层,多层第一GaInP缓冲层逐层渐变,呈现阶梯渐变趋势,通过在In组分阶变的相邻两层第一GaInP缓冲层之间插入In组分阶变方向相反的第二GaInP缓冲层,形成In组分波动渐变的结构,从而在缓冲层中引入压缩应力,增加了位错的相互作用,使表面更平滑,并进一步降低了穿透位错,提高了在氟金云母衬底上的外延层质量,实现了氟金云母衬底在半导体器件的运用。VCSEL具有可弯折、易剥离、外延层质量好、出光效率高等优点。(The invention provides semiconductor epitaxial structures based on flexible substrates, VCSELs and a manufacturing method, wherein fluorophlogopite is used as a substrate, the problems that an existing semiconductor substrate cannot be bent and is not easy to strip are solved, the temperature requirement of a semiconductor device is also considered, for a buffer layer, a plurality of GaInP buffer layers gradually change layer by layer to present a step gradual change trend, a second GaInP buffer layer with opposite In component step changing directions is inserted between two adjacent GaInP buffer layers with In component step changing, and a structure with In component fluctuation and gradual change is formed, so that compressive stress is introduced into the buffer layer, the interaction of dislocation is increased, the surface is smoother, the threading dislocation is further reduced by , the quality of epitaxial layers on the fluorophlogopite substrate is improved, and the application of the fluorophlogopite substrate In the semiconductor device is realized.)

A semiconductor epitaxial structure based on a flexible substrate, comprising a fluorophlogopite substrate and a buffer layer arranged on the fluorophlogopite substrate, wherein the buffer layer comprises:

the multilayer structure comprises a plurality of GaInP buffer layers and at least second GaInP buffer layers, wherein the GaInP buffer layers are sequentially arranged from bottom to top, In components gradually change layer by layer, the second GaInP buffer layers are arranged between two adjacent GaInP buffer layers, the second GaInP buffer layers and two adjacent GaInP buffer layers are In step change, and the step change direction is opposite to the gradual change direction of the GaInP buffer layers.

2. A semiconductor epitaxial structure on the basis of flexible substrate according to claim 1, wherein the second GaInP buffer layer is a multilayer, and a second GaInP buffer layer is provided between the fluorophlogopite substrate and the adjacent GaInP buffer layer, and the second GaInP buffer layer and the adjacent GaInP buffer layer have a step change opposite to the gradient direction of the GaInP buffer layers.

3. The flexible substrate-based semiconductor epitaxial structure of claim 2, wherein the In composition of the th GaInP buffer layer decreases layer by layer, and the In composition of the second GaInP buffer layer is respectively higher than that of the th GaInP buffer layer adjacent thereto.

4. The flexible substrate-based semiconductor epitaxial structure according to claim 3, wherein In compositions of the multiple layers of the second GaInP buffer layer are the same.

5. The flexible substrate-based semiconductor epitaxial structure according to claim 3, wherein the In composition of the second GaInP buffer layers of the plurality of layers decreases layer by layer from bottom to top.

6. The flexible substrate-based semiconductor epitaxial structure of claim 1, wherein the In composition In the GaInP buffer layer and the second GaInP buffer layer ranges from 0.48 to 0.62, respectively.

7. The flexible substrate based semiconductor epitaxial structure of claim 1, wherein the th layer of the buffer layer has a lattice constant higher than the lattice constant of the fluorophlogopite substrate, and the last layer of the buffer layer has a lattice constant lower than the lattice constant of the fluorophlogopite substrate.

8, A method for manufacturing a semiconductor epitaxial structure based on a flexible substrate, comprising the following steps:

providing fluorophlogopite substrate;

growing a buffer layer on the fluorophlogopite substrate, the buffer layer comprising:

the multilayer structure comprises a plurality of GaInP buffer layers and at least second GaInP buffer layers, wherein the GaInP buffer layers are sequentially arranged along the growth direction, In components gradually change layer by layer, the second GaInP buffer layers are arranged between two adjacent GaInP buffer layers, the second GaInP buffer layers and two adjacent GaInP buffer layers are In step change, and the step change direction is opposite to the gradual change direction of the GaInP buffer layers.

A VCSEL 9, , comprising the semiconductor epitaxial structure based on the flexible substrate of any of claims 1 to 7, further comprising an N-type DBR layer, a MQW layer, an oxide layer and a P-type DBR layer sequentially stacked on the buffer layer.

10, method for manufacturing VCSELs, comprising:

providing fluorophlogopite substrate;

the buffer layer grows on the fluorophlogopite substrate and comprises a plurality of layers of GaInP buffer layers and at least layers of second GaInP buffer layers, wherein the plurality of layers of GaInP buffer layers are sequentially arranged along the growth direction, and In components gradually change layer by layer;

and sequentially growing an N-type DBR layer, a multi-quantum well layer, an oxide layer and a P-type DBR layer on the side of the buffer layer, which is far away from the fluorophlogopite substrate.

Technical Field

The invention relates to the technical field of semiconductors, in particular to semiconductor epitaxial structures based on flexible substrates, a VCSEL and a manufacturing method.

Background

The VCSEL, which is named as Vertical Cavity Surface emitting Laser (Vertical Cavity emitting Laser), is developed based on gallium arsenide semiconductor materials, is different from other light sources such as LED (light emitting Diode) and LD (Laser Diode), and has the advantages of small volume, circular output light spot, single longitudinal mode output, small threshold current, low price, easy integration into large-area arrays, and the like, and is widely applied to the fields of optical communication, optical interconnection, optical storage, and the like.

The existing VCSEL usually has a GaAs substrate as a base, however, the GaAs substrate has limited applications of the VCSEL in flexible devices due to physical properties of being inflexible, having poor mechanical properties, being not easy to peel off, and the like. And GaAs substrates absorb light with a wavelength below 870nm, limiting device performance.

Most of the conventional flexible substrates are made of organic materials such as PET (polyethylene terephthalate), but the application temperature of the PET materials is below 200 ℃, so that the requirements of semiconductor devices such as VCSELs (vertical cavity surface emitting devices) cannot be met.

The molecular formula of the fluorophlogopite single crystal sheet is KMg₃(AlSi₃O₁₀)F₂The layered silicate is a typical layered silicate belonging to the monoclinic system. The temperature resistance is up to more than 1200 ℃, the vacuum air release is extremely low under the high temperature condition, and the coating has the characteristics of acid and alkali resistance, transparency, stripping, flexibility and the like. In the current research, only a C60 film or metal (such as molybdenum-tungsten-selenium alloy) is grown on fluorophlogopite, but fluorophlogopite is not used as a semiconductor epitaxial substrate, because the growth of a semiconductor epitaxial layer on the fluorophlogopite substrate is difficult.

Therefore, it is of great significance to apply fluorophlogopite as a substrate in semiconductor devices such as VCSELs.

Disclosure of Invention

Accordingly, the present invention is directed to providing semiconductor epitaxial structures based on flexible substrates and methods for fabricating the same, wherein fluorophlogopite is used as the substrate, and the problem of applying fluorophlogopite in semiconductor devices can be effectively solved, such that the semiconductor devices have flexible characteristics, and providing VCSELs and methods for fabricating the same, wherein the VCSELs have advantages of being bendable, easy to peel off, high in light extraction efficiency, and the like.

The technical scheme adopted by the invention is as follows:

A semiconductor epitaxial structure based on flexible substrate, comprising a fluorophlogopite substrate and a buffer layer arranged on the fluorophlogopite substrate, wherein the buffer layer comprises:

the multilayer structure comprises a plurality of GaInP buffer layers and at least second GaInP buffer layers, wherein the GaInP buffer layers are sequentially arranged from bottom to top, In components gradually change layer by layer, the second GaInP buffer layers are arranged between two adjacent GaInP buffer layers, the second GaInP buffer layers and two adjacent GaInP buffer layers are In step change, and the step change direction is opposite to the gradual change direction of the GaInP buffer layers.

, the second GaInP buffer layer is multi-layer, a second GaInP buffer layer is arranged between the fluorophlogopite substrate and the adjacent GaInP buffer layer, and the second GaInP buffer layer and the adjacent GaInP buffer layer are in a step change opposite to the gradual change direction of the multi-layer GaInP buffer layer.

, the In composition of the GaInP buffer layers decreases layer by layer, and the In composition of the second GaInP buffer layers is higher than that of the GaInP buffer layers adjacent to the second GaInP buffer layers.

Further , the In composition of the second GaInP buffer layers of the plurality of layers is the same.

, the In component of the second GaInP buffer layer decreases from bottom to top.

Further , the In composition of the GaInP buffer layer and the second GaInP buffer layer is In the range of 0.48-0.62.

Further , the th layer of the buffer layer has a lattice constant higher than the lattice constant of the fluorophlogopite substrate and the last layer of the buffer layer has a lattice constant lower than the lattice constant of the fluorophlogopite substrate.

The invention adopts another technical schemes as follows:

A method for manufacturing a semiconductor epitaxial structure based on a flexible substrate comprises the following steps:

providing fluorophlogopite substrate;

growing a buffer layer on the fluorophlogopite substrate, the buffer layer comprising:

the multilayer structure comprises a plurality of GaInP buffer layers and at least second GaInP buffer layers, wherein the GaInP buffer layers are sequentially arranged along the growth direction, In components gradually change layer by layer, the second GaInP buffer layers are arranged between two adjacent GaInP buffer layers, the second GaInP buffer layers and two adjacent GaInP buffer layers are In step change, and the step change direction is opposite to the gradual change direction of the GaInP buffer layers.

The invention adopts technical schemes as follows:

VCSELs comprise the semiconductor epitaxial structure based on the flexible substrate, and further comprise an N-type DBR layer, a multi-quantum well layer, an oxide layer and a P-type DBR layer which are sequentially stacked on the buffer layer.

The invention adopts another technical schemes as follows:

a method of fabricating VCSELs, comprising:

providing fluorophlogopite substrate;

the buffer layer grows on the fluorophlogopite substrate and comprises a plurality of layers of GaInP buffer layers and at least layers of second GaInP buffer layers, wherein the plurality of layers of GaInP buffer layers are sequentially arranged along the growth direction, and In components gradually change layer by layer;

and sequentially growing an N-type DBR layer, a multi-quantum well layer, an oxide layer and a P-type DBR layer on the side of the buffer layer, which is far away from the fluorophlogopite substrate.

From the above description it follows that:

(1) the buffer layer is gradually changed layer by layer to present a step gradual change trend, and a second GaInP buffer layer with opposite In component step changing directions is inserted between two adjacent GaInP buffer layers with In component steps to form a structure with In component fluctuation gradual change, so that compressive stress is introduced into the buffer layer, the interaction of dislocation is increased, the surface is smoother, threading dislocation is further reduced by , the quality of an epitaxial layer on the fluorophlogopite substrate is improved, and the application of the fluorophlogopite substrate In a semiconductor device is realized.

(2) According to the manufacturing method of the semiconductor epitaxial structure based on the flexible substrate, the buffer layer grows on the fluorophlogopite substrate In the mode that the In component fluctuates and gradually changes, the compressive stress is introduced into the buffer layer, the growth difficulty of the buffer layer on the fluorophlogopite substrate is reduced to a great extent, the epitaxial layer with smooth surface and high crystal quality is manufactured, the problem that the buffer layer is not easy to grow when the fluorophlogopite is used as the semiconductor substrate is effectively solved, and the application of the fluorophlogopite substrate In a semiconductor device is realized.

(3) The VCSEL adopts fluorophlogopite as a substrate and a special buffer layer design with gradually changed In component fluctuation, and has the advantages of being bendable, easy to strip, good In epitaxial layer quality, high In light emitting efficiency and the like.

(4) The VCSEL manufacturing method can manufacture the VCSEL which is bendable, easy to strip, good in epitaxial layer quality and high in light emitting efficiency, and is simple in manufacturing process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a flexible substrate-based semiconductor epitaxial structure according to an embodiment of the present invention;

fig. 2 is a schematic diagram of In composition of a buffer layer of a semiconductor epitaxial structure based on a flexible substrate varying with thickness from bottom to top according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a VCSEL device according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a semiconductor epitaxial structure of an embodiment of the present invention;

fig. 5 is a schematic view of a semiconductor epitaxial structure of a flexible substrate-based semiconductor epitaxial structure according to an embodiment of the present invention, wherein the lattice constant from bottom to top varies with thickness;

fig. 6 is a schematic structural diagram of a VCSEL according to a third embodiment of the present invention.

1. The quantum well structure comprises a fluorophlogopite substrate, a2 th buffer layer, a 21 st th GaInP buffer layer, a 22 nd second GaInP buffer layer, a3 rd N-type DBR layer, a 4 th multi-quantum well layer, a 5 th oxide layer, a 6 th P-type DBR layer, a 7 th th separation limiting heterojunction and a 8 th second separation limiting heterojunction.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only partial embodiments of of the present invention, rather than all embodiments.

Please refer to fig. 1-6:

the invention provides semiconductor epitaxial structures based on flexible substrates, which comprises a fluorophlogopite substrate 1 and a buffer layer 2 arranged on the fluorophlogopite substrate 1, wherein the buffer layer 2 comprises:

the multilayer GaInP buffer layer 21 and at least layers of second GaInP buffer layers 22 are arranged, the multilayer GaInP buffer layers 21 are sequentially arranged from bottom to top, In components gradually change from layer to layer, the second GaInP buffer layers 22 are arranged between two adjacent layers of GaInP buffer layers 21, the second GaInP buffer layers 22 and two adjacent layers of GaInP buffer layers 21 change In a step mode, the step change direction is opposite to the gradual change direction of the multilayer GaInP buffer layers 21, the In components of the multilayer GaInP buffer layers 21 rise In a step mode or fall In a step mode, the second GaInP buffer layers 22 with opposite In component step change directions are inserted between two adjacent layers of GaInP buffer layers 21, the structure schematic diagram of the semiconductor epitaxial structure based on a flexible substrate is shown In fig. 1, the schematic diagram of the buffer layers with the change of In thickness from bottom to top is shown In fig. 2, wherein the abscissa refers to the thickness, the ordinate refers to the In composition, the In 1 and the a3 are the In composition of the GaInP GaInP buffer layers, the lattice constant of the buffer layers is reduced, and the lattice constant of the buffer layers is shown In the schematic diagram.

, the second GaInP buffer layer 22 is multi-layered, the second GaInP buffer layer 22 is disposed between the fluorophlogopite substrate 1 and the adjacent GaInP buffer layer 21, and the second GaInP buffer layer 22 and the adjacent GaInP buffer layer 21 are in a step change opposite to the gradual change direction of the multi-layered GaInP buffer layer 21.

, the In composition of the GaInP buffer layer 21 decreases layer by layer, and the In composition of the second GaInP buffer layer 22 is higher than that of the GaInP buffer layer 21 adjacent to the second GaInP buffer layer.

Further , the In composition of the multiple layers of the second GaInP buffer layer 22 is the same.

, the In composition of the second GaInP buffer layer 22 decreases layer by layer from bottom to top.

The In composition of the multilayer GaInP buffer layer is preferably gradually reduced and gradually decreased, and the second GaInP buffer layer is gradually increased relative to the adjacent GaInP buffer layer.

The buffer layer of the invention inserts a second GaInP buffer layer with opposite In component step changing directions between two adjacent GaInP buffer layers with In component step changing descending modes, the In component is In a fluctuation descending mode, compression stress is introduced into the buffer layer, and the interaction of dislocation is increased, so that dislocation disappears.

Preferably, the In compositions of the th GaInP buffer layer 21 and the second GaInP buffer layer 22 are In the range of 0.48 to 0.62, respectively, the thicknesses of the respective layers of the buffer layer 2 are the same, and the In compositions are varied.

Further , the lattice constant of the th layer of the buffer layer 2 is higher than that of the fluorophlogopite substrate 1, and the lattice constant of the last layer of the buffer layer 2 is lower than that of the fluorophlogopite substrate 1.

The In component ranges from 0.48 to 0.62, and the lattice constant of GaInP is closer to that of fluorophlogopite substrate. The lattice constant of the buffer layer is adjusted to be reduced from higher than the fluctuation of the substrate to lower than the fluctuation of the fluorophlogopite by controlling the In component of the buffer layer to fluctuate within the range of 0.48-0.62, thereby achieving the purposes of reducing lattice mismatch and dislocation and realizing better growth of an epitaxial layer on the fluorophlogopite substrate.

The invention also provides methods for manufacturing the semiconductor epitaxial structure based on the flexible substrate, which is used for manufacturing the semiconductor epitaxial structure based on the flexible substrate, and comprises the following steps:

providing fluorophlogopite substrate;

growing a buffer layer on the fluorophlogopite substrate, the buffer layer comprising:

the multilayer structure comprises a plurality of GaInP buffer layers and at least second GaInP buffer layers, wherein the GaInP buffer layers are sequentially arranged along the growth direction, In components gradually change layer by layer, the second GaInP buffer layers are arranged between two adjacent GaInP buffer layers, the second GaInP buffer layers and two adjacent GaInP buffer layers are In step change, and the step change direction is opposite to the gradual change direction of the GaInP buffer layers.

The specific arrangement of the buffer layer refers to the above semiconductor epitaxial structure based on the flexible substrate, and is not described herein again.

Referring to fig. 3, the present invention further provides VCSELs, which include the flexible substrate-based semiconductor epitaxial structure, and further include an N-type DBR layer 3, a multiple quantum well layer 4, an oxide layer 5, and a P-type DBR layer 6 sequentially stacked on the buffer layer 2.

The specific arrangement of the buffer layer refers to the above semiconductor epitaxial structure based on the flexible substrate, and is not described herein again.

The invention also provides a manufacturing method of VCSELs, which is used for manufacturing the VCSELs and comprises the following steps:

providing fluorophlogopite substrate;

the buffer layer grows on the fluorophlogopite substrate and comprises a plurality of layers of GaInP buffer layers and at least layers of second GaInP buffer layers, wherein the plurality of layers of GaInP buffer layers are sequentially arranged along the growth direction, and In components gradually change layer by layer;

and sequentially growing an N-type DBR layer, a multi-quantum well layer, an oxide layer and a P-type DBR layer on the side of the buffer layer, which is far away from the fluorophlogopite substrate.

The specific arrangement of the buffer layer refers to the above semiconductor epitaxial structure based on the flexible substrate, and is not described herein again.

According to the invention, through the special design that the In component of the buffer layer is reduced In a fluctuating manner, the epitaxial layer can be better grown on the fluorophlogopite substrate, a better foundation is provided for the VCSEL structure, and the fluorophlogopite substrate is adopted, so that the VCSEL structure has the characteristics of flexibility and easiness In stripping. Meanwhile, the fluorophlogopite substrate does not absorb light of 200nm-2500nm, so that light transmission is increased, external quantum efficiency is improved, and high light extraction rate is realized.

The following are specific embodiments of the present invention: