阅读说明：本技术 提高二维电子气的GaN器件结构的制备方法 (Preparation method of GaN device structure for improving two-dimensional electron gas ) 是由 郁发新 莫炯炯 刘家瑞 于 2020-04-09 设计创作，主要内容包括：本发明提供了一种提高二维电子气的GaN器件结构的制备方法,包括如下步骤：提供一衬底,在所述衬底的上方形成沟道层；在所述沟道层的上方形成第一势垒层；将所述沟道层分为第一区域和第二区域,去除所述第一区域上方的所述第一势垒层；在所述第一区域的上方形成第二势垒层。本发明通过去除沟道层上方的第一势垒层并代以第二势垒层,提高了沟道层的二维电子气密度；通过对沟道层进行表面处理并二次外延生长第二势垒层,减少了因刻蚀损伤及异质材料原位生长所产生的界面缺陷,提升了器件性能。(The invention provides a preparation method of a GaN device structure for improving two-dimensional electron gas, which comprises the following steps: providing a substrate, and forming a channel layer above the substrate; forming a first barrier layer over the channel layer; dividing the channel layer into a first region and a second region, and removing the first barrier layer above the first region; a second barrier layer is formed over the first region. The two-dimensional electron gas density of the channel layer is improved by removing the first barrier layer above the channel layer and replacing the second barrier layer; by carrying out surface treatment on the channel layer and carrying out secondary epitaxial growth on the second barrier layer, the interface defects caused by etching damage and in-situ growth of heterogeneous materials are reduced, and the performance of the device is improved.)

1. A method for preparing a semiconductor device structure is characterized by comprising the following steps:

providing a substrate, and forming a channel layer above the substrate;

forming a first barrier layer over the channel layer;

dividing the channel layer into a first region and a second region, and removing the first barrier layer above the first region;

a second barrier layer is formed over the first region.

2. The method of manufacturing a semiconductor device structure according to claim 1, wherein the substrate comprises a SiC substrate or a Si substrate, the channel layer comprises a GaN layer, the first barrier layer comprises an AlGaN layer, and the second barrier layer comprises an InAlN layer.

3. The method of manufacturing a semiconductor device structure according to claim 2, wherein a transition buffer layer is further formed between the substrate and the channel layer.

4. The method of fabricating a semiconductor device structure according to claim 3, wherein the transition buffer layer comprises an AlGaN layer.

5. The method of manufacturing a semiconductor device structure of claim 2, wherein the method of forming the first barrier layer and the second barrier layer comprises MOCVD.

6. The method of manufacturing a semiconductor device structure according to claim 1, further comprising a step of performing a surface treatment process on the first barrier layer in the first region before forming a second barrier layer over the first region.

7. The method of claim 6, wherein the surface treatment process comprises oxidizing a surface of the first barrier layer to form an oxide layer, and removing the oxide layer using a wet etching process.

8. The method of manufacturing a semiconductor device structure according to claim 1, wherein the second barrier layer is formed over the first barrier layer in addition to over the first region.

9. The method of claim 1, further comprising the step of forming a passivation layer over the second barrier layer after forming the second barrier layer.

10. The method of claim 9, wherein the passivation layer comprises a SiN layer.

Technical Field

The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a preparation method of a GaN device structure for improving two-dimensional electron gas.

Background

The gallium nitride high electron mobility transistor (GaN HEMT) is a heterojunction field effect transistor, can be applied to the fields of ultrahigh frequency and ultrahigh speed devices, and has wide application prospect. GaN HEMTs are devices that form a channel by generating a two-dimensional electron gas (2DEG) mainly by polarization, which is affected by the polarization degree of the AlGaN layer above the GaN channel layer and the quality of the AlGaN/GaN interface.

Currently, the polarization degree of the AlGaN layer is generally improved by increasing the Al composition in the AlGaN layer or increasing the thickness of the AlGaN layer to increase the two-dimensional electron gas density. The higher the Al component in the AlGaN layer is, the thicker the AlGaN layer is, the stronger the polarization effect is generated, and the higher the two-dimensional electron gas density corresponding to the GaN device is.

However, the process capability is limited, the Al component can only be increased to 25-30% generally, and cannot be further increased; due to the fact that lattice mismatch between AlGaN and GaN occurs, the increase of the thickness of the AlGaN layer affects the quality of the material, the distance from a grid to a channel is increased, and the grid control capability of the device is reduced.

Therefore, it is necessary to provide a new method for manufacturing a semiconductor device structure to solve the above problems.

Disclosure of Invention

In view of the above drawbacks of the prior art, an object of the present invention is to provide a method for manufacturing a GaN device structure with improved two-dimensional electron gas, which is used to solve the problem that the two-dimensional electron gas density of a GaN HEMT device cannot be effectively improved in the prior art.

To achieve the above and other related objects, the present invention provides a method for manufacturing a semiconductor device structure, comprising:

providing a substrate, and forming a channel layer above the substrate;

forming a first barrier layer over the channel layer;

dividing the channel layer into a first region and a second region, and removing the first barrier layer above the first region;

a second barrier layer is formed over the first region.

As an alternative of the present invention, the substrate includes a SiC substrate or a Si substrate, the channel layer includes a GaN layer, the first barrier layer includes an AlGaN layer, and the second barrier layer includes an InAlN layer.

As an alternative of the present invention, a transition buffer layer is further formed between the substrate and the channel layer.

As an alternative of the present invention, the transition buffer layer includes an AlGaN layer.

As an alternative of the present invention, the method of forming the first barrier layer and the second barrier layer includes MOCVD.

As an alternative of the present invention, before forming the second barrier layer over the first region, a step of performing a surface treatment process on the first barrier layer in the first region is further included.

As an alternative of the present invention, the surface treatment process includes oxidizing the surface of the first barrier layer to form an oxide layer, and removing the oxide layer using a wet etching process.

As an alternative of the present invention, the second barrier layer is formed over the first barrier layer in addition to the first region.

As an alternative of the present invention, after the second barrier layer is formed, a step of forming a passivation layer over the second barrier layer is further included.

As an alternative of the invention, the passivation layer comprises a SiN layer.

As described above, the present invention provides a method for manufacturing a semiconductor device structure, which has the following beneficial effects:

the invention improves the two-dimensional electronic gas density of the channel layer by introducing a new preparation method of the semiconductor device structure and removing the first barrier layer above the channel layer and replacing the second barrier layer; by carrying out surface treatment on the channel layer and carrying out secondary epitaxial growth on the second barrier layer, the interface defects caused by etching damage and in-situ growth of heterogeneous materials are reduced, and the performance of the device is improved.

Drawings

Fig. 1 is a flow chart illustrating a method for fabricating a semiconductor device structure according to an embodiment of the invention.

Fig. 2 is a schematic cross-sectional view illustrating a first barrier layer formed over a channel layer according to a first embodiment of the invention.

FIG. 3 is a cross-sectional view of the first barrier layer over the first region being removed according to one embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view illustrating the first barrier layer and the passivation layer after being formed according to the first embodiment of the invention.

Description of the element reference numerals

100 substrate

101 channel layer

101a first area

101b second region

102 first barrier layer

103 second barrier layer

104 transition buffer layer

105 passivation layer

S1-S4 Steps 1) -4)

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1 to 4. It should be noted that the drawings provided in the present embodiment are only schematic and illustrate the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.