CN211404521U

CN211404521U - Superlattice quantum dot structure

Info

Publication number: CN211404521U
Application number: CN201921464586.1U
Authority: CN
Inventors: 不公告发明人
Original assignee: Suzhou Chenrui Photoelectric Co ltd
Current assignee: Suzhou Chenrui Photoelectric Co ltd
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2020-09-01
Anticipated expiration: 2029-09-04

Abstract

The utility model relates to a semiconductor device technical field, concretely relates to superlattice quantum dot structure aims at solving among the prior art substrate and compound semiconductor material, has different lattice constants and coefficient of thermal expansion, if direct growth compound semiconductor material is on the substrate, can form the defect and further influence the problem of growth quality and device performance, and its technical essential lies in including the substrate, epitaxial growth has the active layer on the substrate, the active layer is relative substrate one side grows there is one deck or multilayer heterogeneous quantum dot structure; the heterogeneous quantum dot structure comprises inducing layers and a spacing layer which are arranged at intervals, and the inducing layers on the same layer are closer to one side of the substrate than the spacing layer. The utility model discloses can effectively increase the quantum dot size, the formation of the knot point of doing inhibition can effectively realize the passivation layer of separation defect as optical device or electron device, and the preparation technology is with low costs moreover, need not add any new processing equipment and can accomplish.

Description

Superlattice quantum dot structure

Technical Field

The utility model relates to a semiconductor device technical field, concretely relates to superlattice quantum dot structure.

Background

The heterogeneous quantum dot structure relates to the following: according to the material, the material comprises elementary semiconductor materials such as germanium, silicon and the like, and also comprises compound semiconductors such as III group nitrides, phosphides, arsenides, II-VI groups and the like; is divided into nanometer sizes according to the system size, and belongs to the research field of mesoscopic systems and quantum systems. The growth method includes superlattice epitaxial growth technology represented by metal organic chemical vapor deposition, molecular beam epitaxy, hot wall epitaxy and the like, namely epitaxial growth technology capable of growing ultra-thin desert and abrupt interfaces in atomic order; heteroepitaxy represented by materials with different chemical compositions and different forbidden band widths is included according to the types of epitaxial materials.

Quantum dots are tiny crystal structures with dimensions in the nanometer quantum range, and are typically characterized by complete localization of electron wave functions and quantization of energy spectra. The quantum dot structure has some very significant quantization effects, which directly affect various physical properties of the quantum dot, such as electronic structure, transport properties, optical properties, and the like. Therefore, the method has extremely wide device application prospect.

In addition, semiconductor active optical devices and high-speed electronic devices generally need to be grown on compound semiconductor material substrates, but how to integrate optical and electronic devices in recent years enables future chips to be more miniaturized and improved in performance becomes an important subject, and since silicon substrates and compound semiconductor materials have different lattice constants and thermal expansion coefficients, if the compound semiconductor materials are directly grown on the silicon substrates, defects are formed and the growth quality and the characteristics and the performance of the devices are further affected.

SUMMERY OF THE UTILITY MODEL

Therefore, the to-be-solved technical problem of the utility model lies in overcoming substrate and compound semiconductor material among the prior art, having different lattice constant and coefficient of thermal expansion, if direct growth compound semiconductor material is on the substrate, can form the defect and further influence the defect of growth quality and device performance to provide a superlattice quantum dot structure, can effectively improve the size of quantum dot, and avoid the formation of gathering the node.

The above technical purpose of the present invention can be achieved by the following technical solutions:

a superlattice quantum dot structure comprises a substrate, wherein an active layer is epitaxially grown on the substrate, and one or more layers of heterogeneous quantum dot structures are grown on one side, opposite to the substrate, of the active layer;

the heterogeneous quantum dot structure comprises inducing layers and a spacing layer which are arranged at intervals, and the inducing layers on the same layer are closer to one side of the substrate than the spacing layer.

Optionally, the spacer layer is a GaAs layer, and the inducing layer is an InAs layer.

Optionally, the spacer layer has a thickness of less than 20nm and the inducing layer has a thickness of less than 2.5 ML.

The utility model discloses technical scheme has following advantage:

1. the superlattice quantum dot structure of the utility model can effectively block the propagation of dislocation defects through the growth strain layer, further reduce the defect density of semiconductor materials, and utilize the multilayer quantum dot structure as a defect barrier layer, the effect is better, because after the growth of the first layer quantum dot, the thin spacing layer is used as the barrier layer, when the second layer quantum dot is grown, the existing stress can be sensed, the critical thickness of the inducing layer can be effectively reduced, therefore, when the inducing layer with the same thickness is grown, the structure can form larger quantum dots, in addition, because the existing stress of the inducing layer exists at the lower end, when the second layer inducing layer quantum dot is grown, the second layer quantum dots can be formed at the same position, the effect of up-down alignment is formed, thus the problem that the traditional method can be solved that the traditional method is combined with each other to form a gathering point due to too close to or too close to the quantum dot volume is enlarged, the superlattice quantum dot structure can effectively enlarge the size of the quantum dot (except for increasing stress), inhibit the formation of a condensation point and be effectively used as a passivation layer for realizing defect blocking of an optical device or an electronic device.

2. The superlattice quantum dot structure of the utility model is suitable for various epitaxial growth devices commonly used at present, such as Molecular Beam Epitaxy (MBE), Metal Organic Chemical Vapor Deposition (MOCVD), hydride vapor deposition (HVPE), hot wall epitaxy and the like.

3. The superlattice quantum dot structure of the utility model is suitable for various commonly used village bottom materials, and can perform corresponding surface passivation on the materials, thereby reducing the surface energy, namely adopting the method to grow the quantum dots of each material system.

4. The superlattice quantum dot structure of the utility model can grow quantum dots with different scales by using the growth method, and the adjustment range is large.

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 embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a superlattice quantum dot structure according to an embodiment of the present invention.

Description of reference numerals:

1. a substrate; 2. an active layer; 3. a heterogeneous quantum dot structure; 31. an inducing layer; 32. a spacer layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1:

a superlattice quantum dot structure is disclosed, as shown in fig. 1, and comprises a substrate 1, for example, GaAs is adopted as the substrate 1, then an active layer 2 is epitaxially grown on the substrate 1 for passivating the surface of the epitaxially grown material so as to facilitate the formation of quantum dots, and then one or more layers of heterogeneous quantum dot structures 3 are grown on the side of the active layer 2 opposite to the substrate 1; specifically, heterogeneous quantum dot structure 3 includes induced layer 31 and the spacer layer 32 that the interval set up, is located induced layer 31 on the same layer and compares spacer layer 32 and be close to substrate 1 one side, in this embodiment of the utility model discloses spacer layer 32 is the GaAs layer that thickness is less than 20nm, and induced layer 31 is the InAs layer that thickness is less than 2.5 ML. Because lattice mismatching degree of InAs and GaAs is up to 7%, InAs quantum dots are regarded as strain layers which can effectively block dislocation propagation, the InAs quantum dots are formed in the following process, when InAs grows to be thicker than the critical thickness, the stress is released to form quantum dots, if the stress is further increased (dislocation can be more effectively blocked), the quantum dots are increased by continuously growing InAs in the traditional mode, coalescent dots are easily formed to cause defects, and the performance of a device is influenced, so that in order to solve the problem, the utility model discloses a strain layer can effectively block dislocation defect propagation, and further reduce defect density of a semiconductor material, and a multilayer quantum dot structure is used as a defect blocking layer, so that the effect is better, because after a first layer of quantum dots is grown, a thinner spacing layer 32 is used as the blocking layer, and when a second layer of quantum dots is grown, the stress exists below the strain layer, the critical thickness of the inducing layer 31 is effectively reduced, so that when the inducing layer 31 with the same thickness is grown, a larger quantum dot can be formed in the structure, in addition, because the stress of the inducing layer 31 at the lower end exists, when the quantum dot of the inducing layer 31 of the second layer is grown, the quantum dot of the second layer can be formed at the same position to form the effect of vertical alignment, and thus the problem that the traditional material defect is caused because the quantum dots are combined with each other due to too close or too close to each other after the volume of the quantum dot is increased can be solved. Therefore, the superlattice quantum dot structure can effectively increase the size of the quantum dot (except for increasing stress), can also inhibit the formation of a condensation point, and can be effectively used as a passivation layer for realizing defect blocking and defect blocking of an optical device or an electronic device. In addition, in other embodiments, InAs/GaAs is not limited to be used as the quantum dot material, but InGaAs/GaAs can also be used; InAlAs/GaAs; InGaN/GaN; InAs/InP is used as the quantum dot material, and the conditions of the growth thickness, the layer number and the like of the quantum dots can be adjusted according to different selected materials and the degree of lattice mismatching of the substrate.

Example 2:

a method for manufacturing a superlattice quantum dot structure, as shown in fig. 1, includes the following steps:

s1, selecting a substrate 1, and epitaxially growing another material required by the substrate 1 as an active layer 2 for next application, wherein the substrate 1 is a homogeneous substrate or a heterogeneous substrate, except GaAs, spinel (MgAl2O4), silicon carbide (SiC), aluminum nitride (AlN), zinc oxide (ZnO), an alumina composite substrate grown on silicon (Al2O3/Si), an aluminum nitride composite substrate grown on silicon (AlN/Si), a zinc oxide composite substrate grown on silicon (ZnO/Si), AlN/SiC and other heterogeneous composite substrates can be selected, in short, the active layer 2 epitaxially grown on the substrate 1 has good quality and can be used as a template of quantum dots;

s2, passivating the epitaxially grown active layer 2, in this embodiment of the present invention, passivating by oxide to fill dangling bonds on the surface of the substrate 1, and improving the transition barrier of surface atoms, so as to facilitate the formation of quantum dots;

s3, a heterogeneous quantum dot structure 3 is grown on the active layer 2, the heterogeneous quantum dot structure 3 can be used as a passivation layer of an optical device or an electronic device, the interlayer 32 is a GaAs layer with the thickness of less than 20nm, and the induction layer 31 is an InAs layer with the thickness of less than 2.5ML, so that the superlattice quantum dot structure can effectively increase the size of quantum dots (except for stress increase), can also inhibit the formation of a junction point, and can be effectively used as a passivation layer for realizing defect blocking of the optical device or the electronic device;

in this embodiment of the present invention, the optical device includes a light emitting diode, a laser diode or a photodetector, and the electrical device includes a coulomb blockade device, a quantum memory device;

the heterogeneous quantum dot structure 3 comprises an inducing layer 31 and a spacing layer 32 which are sequentially grown at intervals, so that the inducing layer 31 on the same layer is closer to one side of the substrate 1 than the spacing layer 32, and thus propagation of dislocation defects can be effectively blocked by growing a strain layer, and the defect density of a semiconductor material is further reduced.

Example 3:

s3, three layers of heterogeneous quantum dot structures 3 are grown on the active layer 2, the heterogeneous quantum dot structures 3 can be used as passivation layers of optical devices or electronic devices, the interlayer 32 is a GaAs layer with the thickness less than 20nm, the inducing layer 31 is an InAs layer with the thickness less than 2.5ML, so that after the first layer of quantum dots is grown, the thinner interlayer 32 is used as a barrier layer, when the second layer of quantum dots is grown, the existence of the stress below the second layer of quantum dots can be sensed, the critical thickness of the inducing layer 31 is effectively reduced, when the inducing layer 31 with the same thickness is grown, the structure can form larger quantum dots, in addition, due to the existence of the stress of the existing inducing layer 31 at the lower end, when the second layer of inducing layer 31 is grown, the second layer of quantum dots can be formed at the same position, the vertical alignment effect is formed, and therefore, the problem that the traditional quantum dots are combined with each other to form a gathering point due to too close to each other because of too close to each other because the, causing material defects. Therefore, the superlattice quantum dot structure can effectively increase the size of the quantum dot (except for increasing stress), can also inhibit the formation of a junction point, and can be effectively used as a passivation layer of an optical device or an electronic device;

the heterogeneous quantum dot structure 3 comprises an inducing layer 31 and a spacer layer 32 which are sequentially grown at intervals, so that the inducing layer 31 on the same layer is closer to one side of the substrate 1 than the spacer layer 32.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.

Claims

1. A superlattice quantum dot structure is characterized by comprising a substrate (1), wherein an active layer (2) is epitaxially grown on the substrate (1), and one or more layers of heterogeneous quantum dot structures (3) are grown on the active layer (2) opposite to one side of the substrate (1);

the heterogeneous quantum dot structure (3) comprises an inducing layer (31) and a spacing layer (32) which are arranged at intervals, and the inducing layer (31) on the same layer is closer to one side of the substrate (1) than the spacing layer (32).

2. A superlattice quantum dot structure as claimed in claim 1, wherein said spacer layer (32) is a GaAs layer and said inducing layer (31) is an InAs layer.

3. A superlattice quantum dot structure as claimed in claim 2, characterized in that said spacer layer (32) has a thickness of less than 20nm and said inducing layer (31) has a thickness of less than 2.5 ML.