CN106783955B - Semiconductor device including an insertion layer of aluminum gallium nitride and indium gallium nitride and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride and a method for manufacturing the same. The semiconductor device comprises a substrate, a seed layer disposed on the substrate, a buffer layer disposed on the seed layer, a III-group nitride epitaxial layer disposed on the buffer layer, and an insertion layer disposed in the middle of the III-group nitride epitaxial layer, wherein the insertion layer comprises an aluminum gallium nitride layer and/or an indium gallium nitride layer. The present invention can compensate for a portion of the tensile stress in the III-group nitride epitaxial layer by disposing the insertion layer, effectively reduce the dislocation and tensile stress of the III-group nitride epitaxial layer, and obtain a high-quality III-group nitride epitaxial layer.

Description

Semiconductor device containing insertion layer of aluminum gallium nitride and indium gallium nitride and method for manufacturing the same

Technical Field

The present invention relates to the field of semiconductor devices, and in particular to a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride and a manufacturing method thereof.

Background Art

Group III nitride semiconductor materials are known as the third generation of semiconductor materials, including gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN) and ternary and quaternary alloys formed between them, such as aluminum gallium nitride (AlGaN), indium aluminum nitride (InAlN) and indium gallium nitride (InGaN). Group III nitride semiconductor materials, mainly gallium nitride (GaN), have a wide direct generation gap (Eg = 3.36eV), a high melting point, high thermal conductivity, high saturation electron velocity, high critical breakdown electric field strength and high electron room temperature mobility. They are widely used in metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), heterojunction field effect transistors (HFETs), light emitting diodes (LEDs) and other high temperature resistant, high voltage and high frequency switching devices.

Since it is difficult to obtain large-sized III-nitride single crystal materials at present, in order to obtain high-quality III-nitride epitaxial layers, heteroepitaxial growth is generally performed on substrate materials such as silicon, sapphire or silicon carbide. However, as the thickness of the III-nitride epitaxial layer increases, more dislocation defects and greater internal stress will be generated on the III-nitride film, resulting in cracks in the III-nitride epitaxial layer, which seriously affects the performance of semiconductor devices.

Summary of the invention

Based on this, it is necessary to provide a semiconductor device and a manufacturing method thereof containing an insertion layer of aluminum gallium nitride and indium gallium nitride to address the problem that more dislocation defects and greater internal stress will be generated on the group III nitride film as the thickness of the group III nitride epitaxial layer increases.

A semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride, characterized by comprising:

substrate;

A seed layer, the seed layer being disposed on an upper portion of the substrate;

a buffer layer, the buffer layer being disposed on an upper portion of the seed crystal layer;

A group III nitride epitaxial layer, wherein the group III nitride epitaxial layer is disposed on an upper portion of the buffer layer;

and an insertion layer, wherein the insertion layer is arranged in the middle of the group III nitride epitaxial layer, and the insertion layer includes an aluminum gallium nitride layer and an indium gallium nitride layer.

In one embodiment, the insertion layer includes a single-layer aluminum gallium nitride layer and a single-layer indium gallium nitride layer.

In one embodiment, the aluminum gallium nitride layer and/or the indium gallium nitride layer is a multilayer, and the indium gallium nitride layer and the aluminum gallium nitride layer are alternately stacked.

In one of the embodiments, when there are multiple layers of the AlGaN layer, the doping concentration of aluminum in each layer of the AlGaN layer is different, and the doping concentration of aluminum in the AlGaN layer is less than or equal to 1.

In one of the embodiments, the III-nitride epitaxial layer is provided with a plurality of the insertion layers.

In one embodiment, the substrate is a sapphire substrate, a silicon substrate or a silicon carbide substrate.

In one embodiment, the seed layer is an aluminum nitride layer and/or an aluminum gallium nitride layer.

In one embodiment, the buffer layer is an aluminum nitride layer and/or an aluminum gallium nitride layer.

In one embodiment, the III-nitride epitaxial layer includes at least one of a gallium nitride epitaxial layer and an aluminum gallium nitride epitaxial layer, and the III-nitride epitaxial layer has a heterostructure consisting of the gallium nitride epitaxial layer and the aluminum gallium nitride epitaxial layer.

In the semiconductor device, an insertion layer composed of a stacked aluminum gallium nitride layer and an indium gallium nitride layer is inserted in the middle of the III-nitride epitaxial layer. The structure of the aluminum gallium nitride layer in the insertion layer is adjusted by changing the aluminum doping concentration, which effectively alleviates the lattice mismatch and thermal mismatch between the III-nitride epitaxial layer and the substrate; and the compressive stress in the insertion layer can compensate for a part of the tensile stress in the III-nitride epitaxial layer, effectively reducing the dislocation and tensile stress of the III-nitride epitaxial layer. Therefore, a high-quality III-nitride epitaxial layer can be obtained by setting an insertion layer containing aluminum gallium nitride and indium gallium nitride.

In addition, it is also necessary to provide a method for manufacturing a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride.

A method for manufacturing a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride, characterized in that the manufacturing method comprises the following steps:

1) forming a seed layer on a substrate;

2) forming a buffer layer on the seed layer;

3) forming a group III nitride epitaxial layer on the buffer layer;

4) forming an insertion layer on the surface of the pre-grown III-nitride layer, and then continuing to grow the III-nitride on the insertion layer to form the III-nitride epitaxial layer with the pre-grown III-nitride layer, wherein the insertion layer includes an aluminum gallium nitride layer and an indium gallium nitride layer.

The semiconductor device containing the insertion layer of aluminum gallium nitride and indium gallium nitride manufactured by this method has a high critical breakdown electric field strength and a high electron room temperature mobility, and the working performance of the semiconductor device is good.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride according to an embodiment;

FIG. 2 is a schematic diagram of the structure of an insertion layer of a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride according to one embodiment.

DETAILED DESCRIPTION

In order to facilitate the understanding of the present invention, a semiconductor device containing a silicon-doped aluminum nitride layer and a method for manufacturing the same will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and/or" used herein includes any and all combinations of one or more related listed items.

As shown in FIG. 1 , a semiconductor device according to an embodiment includes a substrate 101 , a seed layer 102 , a buffer layer 103 , a first group III nitride epitaxial layer 104 , an insertion layer 105 , and a second group III nitride epitaxial layer 106 .

In this embodiment, the material selection of the substrate 101 should not only consider the lattice mismatch and the thermal expansion coefficient of the material, but also comprehensively consider the size and price of the material. In this embodiment, the material of the substrate 101 is silicon. It is understood that in other embodiments, the material of the substrate 101 can also be sapphire or silicon carbide.

The seed layer 102 is located on the upper surface of the substrate 101, and its main function is to form nucleation points on the substrate surface, which is conducive to the nucleation and growth of group III nitrides on the substrate. In this embodiment, the material of the seed layer 102 is aluminum nitride. The seed layer 102 is constructed of one or more layers of aluminum nitride layers. Preferably, the thickness of the seed layer 102 is less than or equal to 500nm. It is understood that in other embodiments, the material of the seed layer 102 is other group III nitrides such as aluminum gallium nitride, gallium nitride, silicon nitride, or a combination of several. The seed layer 102 is a one-layer or multi-layer structure composed of other group III nitride layers such as aluminum nitride, gallium nitride, and silicon nitride.

The buffer layer 103 is located on the upper part of the seed layer 102. Its main function is to effectively alleviate the lattice mismatch and thermal mismatch between the III-nitride epitaxial layer and the substrate, reduce the strain of the III-nitride epitaxial layer caused by stress, and reduce the occurrence of dislocations and defects. In this embodiment, the material of the buffer layer 103 is gallium aluminum nitride. The buffer layer 103 is constructed of one or more layers of gallium aluminum nitride. Preferably, the thickness of the buffer layer 103 is less than or equal to 5um. It is understood that in other embodiments, the material of the buffer layer 103 is aluminum nitride, gallium nitride, silicon nitride and other III-nitrides, or a combination of several. The buffer layer 103 is a layer or multilayer structure composed of other III-nitride layers such as aluminum nitride layers, gallium nitride layers, and silicon nitride layers.

The III-nitride epitaxial layer is composed of a first III-nitride epitaxial layer 104 and a second III-nitride epitaxial layer 106. The first III-nitride epitaxial layer 104 is located on the upper portion of the buffer layer 103, and the second III-nitride epitaxial layer 106 is located on the upper portion of the first III-nitride epitaxial layer 104. In this embodiment, the material of the first III-nitride epitaxial layer 104 is gallium nitride, and the material of the second III-nitride epitaxial layer 106 is aluminum gallium nitride.

A gallium nitride aluminum/gallium nitride heterostructure is formed between the gallium nitride epitaxial layer and the gallium nitride aluminum epitaxial layer. The gallium nitride aluminum/gallium nitride heterostructure is the core component of semiconductor devices. A triangular potential well is formed at the gallium nitride aluminum/gallium nitride heterostructure interface. The de Broglie wavelength of electrons is larger than the width of the potential well. The energy perpendicular to the surface will be quantized to form a sub-band. The electrons lose their freedom in the direction perpendicular to the surface and only have freedom in two directions along the surface. The electrons with very high migration speed in these potential wells are two-dimensional electron gas (2DEG).

It can be understood that in other embodiments, the material of the first III-nitride epitaxial layer 104 is other III-nitrides such as aluminum gallium nitride or indium gallium nitride, and the material of the second III-nitride epitaxial layer 106 is other III-nitrides such as gallium nitride or indium nitride. The group III nitride epitaxial layer is a two-layer structure consisting of a first group III nitride epitaxial layer 104 and a second group III nitride epitaxial layer 106, a three-layer structure consisting of two first group III nitride epitaxial layers 104 and a second group III nitride epitaxial layer 106, a three-layer structure consisting of a first group III nitride epitaxial layer 104 and two second group III nitride epitaxial layers 106, a four-layer structure consisting of two first group III nitride epitaxial layers 104 and two second group III nitride epitaxial layers 106, etc., including a multilayer structure consisting of the first group III nitride epitaxial layer 104 and the second group III nitride epitaxial layer 106, and the group III nitride epitaxial layer has at least one heterostructure.

The insertion layer 105 is located in the middle of the III-nitride epitaxial layer, and its main function is to put the subsequently grown epitaxial layer in a compressive strain state, reduce the stress and dislocation in the epitaxial layer, and then eliminate the cracks in the epitaxial layer to obtain a high-quality, crack-free III-nitride epitaxial layer. In this embodiment, the insertion layer 105 is located in the middle of the first III-nitride epitaxial layer 104, and the material of the insertion layer 105 is gallium indium nitride and gallium aluminum nitride, wherein the aluminum nitride material can change the aluminum doping concentration (the mass fraction of aluminum relative to the aluminum nitride layer) according to the requirements of epitaxial layer growth. Preferably, the thickness of the insertion layer 105 is less than or equal to 100nm.

As shown in FIG2 , the insertion layer 105 is a superlattice layer structure formed by alternately stacking and growing gallium aluminum nitride layers 111 and gallium indium nitride layers 112. Among them, the doping concentration of aluminum in the second gallium aluminum nitride layer 111 in the insertion layer 105 is increased by 15% relative to the doping concentration of aluminum in the first gallium aluminum nitride layer 111, the doping concentration of aluminum in the third gallium aluminum nitride layer 111 is increased by 35% relative to the doping concentration of aluminum in the first gallium aluminum nitride layer 111, and the doping concentration of aluminum in the third gallium aluminum nitride layer 111 is increased by 60% relative to the doping concentration of aluminum in the first gallium aluminum nitride layer 111. The doping concentration of aluminum in each gallium aluminum nitride layer 111 in the insertion layer 105 may not be fixed, and the doping concentration of aluminum in each gallium aluminum nitride layer 111 may be adjusted according to the growth requirements of the III-group nitride epitaxial layer, and may change irregularly. Preferably, the doping concentration of aluminum in the gallium aluminum nitride layer 111 is less than or equal to 1.

It can be understood that in other embodiments, the insertion layer 105 can be a two-layer structure consisting of a single-layer aluminum gallium nitride layer 111 and a single-layer indium gallium nitride layer 112, a three-layer structure consisting of two aluminum gallium nitride layers 111 and a single-layer indium gallium nitride layer 112, a three-layer structure consisting of a single-layer aluminum gallium nitride layer 111 and two indium gallium nitride layers 112, a four-layer structure consisting of two aluminum gallium nitride layers 111 and two indium gallium nitride layers 112, a five-layer structure consisting of three aluminum gallium nitride layers 111 and two indium gallium nitride layers 112, etc., in which the aluminum gallium nitride layers 111 and the indium gallium nitride layers 112 are alternately stacked and grown to form a superlattice layer structure. Among them, the doping concentration of aluminum in each aluminum gallium nitride layer 111 in the insertion layer 105 can be fixed or not fixed. The doping concentration of aluminum in each aluminum gallium nitride layer 111 can be adjusted according to the growth requirements of the III-group nitride epitaxial layer, and can be regularly changed or irregularly changed. Preferably, the doping concentration of aluminum in the aluminum gallium nitride layer 111 is less than or equal to 1.

Preferably, there are a plurality of insertion layers 105 including aluminum gallium nitride layers 111 and indium gallium nitride layers 112 in the first group III nitride epitaxial layer 104 and the first group III nitride epitaxial layer 106 .

In addition, this embodiment also provides a method for manufacturing the semiconductor device containing the silicon-doped aluminum nitride layer, which specifically includes the following steps:

Step 1: depositing a seed layer 102 containing silicon-doped aluminum nitride on a provided substrate 101 .

In this embodiment, the seed layer 102 is formed by a method of vapor phase epitaxial growth (MOCDV) by implanting trimethylaluminum in an NH 3 atmosphere at a temperature above 1000 degrees.

Before forming the seed layer 102 , a step of removing the natural oxide layer of the substrate 101 by wet etching or dry etching is also included.

Step 2: forming a buffer layer 103 on the seed layer 102 .

Step three: forming nucleation points on the buffer layer 103 to promote island growth and island merging of group III nitrides, and gradually forming the first group III nitride epitaxial layer 104 .

Step 4: forming an insertion layer 105 on the surface of the pre-grown group III nitride layer, and then continuing to grow group III nitride on the insertion layer 105 to form a first group III nitride epitaxial layer 104 with the pre-grown group III nitride layer. Forming the insertion layer 105 in the first group III nitride epitaxial layer 104 can reduce the internal stress and dislocation generated as the thickness of the group III nitride layer increases.

Step 5: forming a second group III nitride epitaxial layer 106 on the first group III nitride epitaxial layer 104 to complete the growth of the group III nitride epitaxial layer.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims (9)

1. A semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride, characterized in that it comprises: substrate; A seed layer, the seed layer being arranged on the upper part of the substrate; a buffer layer, the buffer layer being disposed on an upper portion of the seed crystal layer; a group III nitride epitaxial layer, wherein the group III nitride epitaxial layer is disposed on an upper portion of the buffer layer; and An insertion layer, wherein the insertion layer is arranged in the middle of the III-group nitride epitaxial layer, and the insertion layer includes a gallium aluminum nitride layer and a gallium indium nitride layer; the gallium aluminum nitride layer is four layers, the gallium indium nitride layer is three layers, and the gallium indium nitride layer and the gallium aluminum nitride layer are adjacent to each other and are alternately stacked and grown in sequence to form a superlattice layer structure; the doping concentration of aluminum in each layer of the gallium aluminum nitride layer is different, wherein the doping concentration of aluminum in the second layer of the gallium aluminum nitride layer is increased by 15% relative to the doping concentration of aluminum in the first layer of the gallium aluminum nitride layer, and the doping concentration of aluminum in the third layer of the gallium aluminum nitride layer is increased by 35% relative to the doping concentration of aluminum in the first layer of the gallium aluminum nitride layer, and the doping concentration of aluminum in the gallium aluminum nitride layer is less than or equal to 1; The III-nitride epitaxial layer is composed of a first III-nitride epitaxial layer and a second III-nitride epitaxial layer, the material of the first III-nitride epitaxial layer is gallium nitride, the material of the second III-nitride epitaxial layer is gallium nitride aluminum, and the insertion layer is located in the middle of the first III-nitride epitaxial layer. 2 . The semiconductor device according to claim 1 , wherein the group III nitride epitaxial layer is provided with a plurality of the insertion layers. 3 . The semiconductor device according to claim 1 , wherein the substrate is a sapphire substrate, a silicon substrate or a silicon carbide substrate. 4 . The semiconductor device according to claim 1 , wherein the seed layer is an aluminum nitride layer and/or an aluminum gallium nitride layer. 5 . The semiconductor device according to claim 1 , wherein the buffer layer is an aluminum nitride layer and/or an aluminum gallium nitride layer. The semiconductor device according to claim 1 , wherein the thickness of the seed layer is less than or equal to 500 nm. 7 . The semiconductor device according to claim 1 , wherein the buffer layer has a thickness less than or equal to 5 μm. 8 . The semiconductor device according to claim 1 , wherein the thickness of the insertion layer is less than or equal to 100 nm. 9. A method for manufacturing a semiconductor device containing an insertion layer of aluminum gallium nitride and indium gallium nitride, characterized in that the manufacturing method comprises the following steps: 1) depositing a seed crystal layer containing silicon-doped aluminum nitride on a substrate; 2) forming a buffer layer on the seed layer; 3) forming nuclei on the buffer layer to promote island growth and island merging of group III nitrides, and gradually forming a first group III nitride epitaxial layer; 4) forming an insertion layer on the surface of the pre-grown III-nitride layer, and then continuing to grow the III-nitride on the insertion layer to form the first III-nitride epitaxial layer with the pre-grown III-nitride layer, wherein the insertion layer comprises a gallium aluminum nitride layer and a gallium indium nitride layer; the gallium aluminum nitride layer is four layers, the gallium indium nitride layer is three layers, and the gallium indium nitride layer and the gallium aluminum nitride layer are adjacent to each other and are alternately stacked and grown in sequence to form a superlattice layer structure; the doping concentration of aluminum in each layer of the gallium aluminum nitride layer is different, wherein the doping concentration of aluminum in the second layer of the gallium aluminum nitride layer is increased by 15% relative to the doping concentration of aluminum in the first layer of the gallium aluminum nitride layer, and the doping concentration of aluminum in the third layer of the gallium aluminum nitride layer is increased by 35% relative to the doping concentration of aluminum in the first layer of the gallium aluminum nitride layer, and the doping concentration of aluminum in the gallium aluminum nitride layer is less than or equal to 1; 5) Forming a second Group III nitride epitaxial side on the first Group III nitride epitaxial layer.