CN109037153A - A kind of preparation method and gallium nitride Base HEMT device of gallium nitride Base HEMT device - Google Patents

Abstract

The present application provides a preparation method of a gallium nitride-based HEMT device and a gallium nitride-based HEMT device. The method comprises: sequentially epitaxially growing a buffer layer, a channel layer, and a barrier layer on a pre-selected substrate; depositing a passivation layer on the barrier layer; A part of the layer is etched to form a groove; p-type gallium nitride is regrown in the groove so that p-type gallium nitride fills the groove; The first source and the first drain are plugged into the channel layer; a second source and a second drain are formed on one side of the first drain; on the p-type gallium nitride forming a first gate; forming a second gate on the second source and the second drain. Using various embodiments in the present application, a GaN-based HEMT device with two characteristics of normally-on and normally-off can be obtained on the same wafer.

Description

Preparation method of gallium nitride-based HEMT device and gallium nitride-based HEMT device

technical field

The present application relates to the field of semiconductor technology, in particular to a preparation method of a gallium nitride-based HEMT device and a gallium nitride-based HEMT device.

Background technique

Gallium nitride-based HEMT (High Electron Mobility Transistor, HEMT for short) device has two-dimensional electron gas between its barrier layer and channel layer, due to the existence of the two-dimensional electron gas, resulting in nitrogen GaN-based HEMT devices are normally-on devices.

However, in the prior art, when GaN-based HEMT devices are installed and used in actual electronic circuits, it is usually necessary to implement two functions of normally open and normally closed on the same chip at the same time, such as in a frequency converter. However, in the prior art, there is no GaN-based HEMT device capable of both normally-on performance and normally-off performance on the same wafer, and there is no method for preparing such a device.

There are at least the following problems in the prior art: there is no Gallium Nitride-based HEMT device capable of both normally-on performance and normally-off performance on the same wafer in the prior art, and there is no method for preparing such a device.

Contents of the invention

The purpose of the embodiment of the present application is to provide a preparation method of a gallium nitride-based HEMT device and a gallium nitride-based HEMT device, so as to obtain a gallium nitride-based HEMT devices.

The embodiment of the present application provides a method for preparing a gallium nitride-based HEMT device and the gallium nitride-based HEMT device is realized as follows:

A method for preparing a gallium nitride-based HEMT device, the method comprising:

Epitaxial growth of buffer layer, channel layer, and barrier layer in sequence on a pre-selected substrate;

depositing a passivation layer on the barrier layer;

etching a portion of the passivation layer and the barrier layer to form a groove, the groove penetrating through the passivation layer and stopping at the barrier layer;

Regrowing p-type gallium nitride in the groove by using a vapor phase epitaxy growth process, so that the p-type gallium nitride fills the groove;

A first source and a first drain are respectively formed on both sides of the p-type gallium nitride, and both the first source and the first drain are plugged into the channel layer;

forming a second source and a second drain on a side of the first drain away from the p-type gallium nitride;

forming a first gate on the p-type gallium nitride, and forming a Schottky contact with the p-type gallium nitride;

A second gate is formed between the second source and the second drain, and the second gate forms a Schottky contact with the barrier layer.

In a preferred embodiment, the types of substrates include silicon substrates, silicon carbide substrates, and sapphire substrates;

The composition material of the buffer layer includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer includes gallium nitride, and the composition material of the barrier layer includes aluminum gallium nitride;

The composition material of the passivation layer includes silicon dioxide or silicon nitride.

In a preferred embodiment, said depositing and forming a passivation layer on said barrier layer comprises:

After the convex isolation is formed on the barrier layer by etching or ion implantation, the passivation layer is deposited on the barrier layer to form the passivation layer.

In a preferred embodiment, the etching a part of the passivation layer and the barrier layer includes:

A part of the passivation layer and the barrier layer is etched by using a p-type gallium nitride gate mask.

A gallium nitride-based HEMT device, the device comprising:

Substrate;

a buffer layer formed on the substrate;

a gallium nitride channel layer epitaxially grown on said buffer layer;

an aluminum gallium nitride barrier layer epitaxially grown on the gallium nitride channel layer;

a passivation layer deposited on the aluminum gallium nitride barrier layer;

a p-type gallium nitride layer passing through the passivation layer and a part of the aluminum gallium nitride barrier layer, the bottom of the p-type gallium nitride layer being located in the aluminum gallium nitride barrier layer;

A first gate is formed on the p-type gallium nitride layer;

A first source and a first drain are respectively formed on both sides of the first gate, and both the first source and the first drain are plugged into the channel layer;

A second source and a second drain are formed on the side of the first drain away from the first gate, and both the second source and the second drain are plugged into the channel layer ;

A second gate is formed between the second source and the second drain;

A two-dimensional electron gas is formed between the channel layer and the potential barrier layer, and the two-dimensional electron gas in the region directly below the p-type gallium nitride is depleted.

In a preferred embodiment, the substrate, the buffer layer, the barrier layer, the channel layer, the passivation layer, the p-type gallium nitride layer, the first gate, the The first source and the first drain form a normally-off HEMT device;

The buffer layer, the barrier layer, the channel layer, the passivation layer, the second gate, the second source, and the second drain form a normally-on HEMT device.

In a preferred embodiment, the first gate forms a Schottky contact with the p-type GaN layer, and the second gate forms a Schottky contact with the AlGaN barrier layer.

In a preferred embodiment, the first source and the first drain form an ohmic contact with the channel layer, and the second source and the second drain form an ohmic contact with the channel layer .

In a preferred embodiment, the types of substrates include silicon substrates, silicon carbide substrates, and sapphire substrates;

The composition material of the buffer layer includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer includes gallium nitride, and the composition material of the barrier layer includes aluminum gallium nitride;

The composition material of the passivation layer includes silicon dioxide or silicon nitride.

In a preferred embodiment, a convex isolation formed by ion implantation or etching is provided between the barrier layer and the passivation layer.

A normally-on GaN-based HEMT device and a normally-off GaN-based HEMT device on the same wafer can be fabricated by using a method for manufacturing a GaN-based HEMT device provided in an embodiment of the present application. The normally-on HEMT device can be guaranteed to have an optimized barrier structure during epitaxial growth, thereby ensuring its better electrical performance, and the gate threshold voltage of the normally-off HEMT device can be greater than 1V by using the pre-epitaxial growth process. A GaN-based HEMT device provided in an embodiment of the present application, the device includes a normally-on HEMT device and a normally-closed HEMT device, and the two devices are grown on the same wafer, which can effectively increase the application range of the device . At the same time, it can also ensure that both the normally-on HEMT device and the normally-closed HEMT device have optimal electrical performance.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in this application. Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a schematic flow chart of a method for preparing a GaN-based HEMT device provided by an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 3 is a schematic structural diagram obtained in the first preparation step of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 4 is a schematic structural diagram obtained in the second preparation step of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 5 is a schematic structural diagram obtained in the third preparation step of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 6 is a schematic structural diagram obtained in the fourth preparation step of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 7 is a schematic structural diagram obtained in the fifth preparation step of a GaN-based HEMT device provided by an embodiment of the present application;

Fig. 8 is a schematic structural diagram obtained in the sixth preparation step of a GaN-based HEMT device provided by an embodiment of the present application.

Detailed ways

Embodiments of the present application provide a method for manufacturing a gallium nitride-based HEMT device and a gallium nitride-based HEMT device.

In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described The embodiments are only some of the embodiments of the present application, but not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

FIG. 1 is a schematic flow chart of an embodiment of a method for manufacturing a gallium nitride-based HEMT device described in the present application. Although the present application provides method operation steps or structures as shown in the following embodiments or drawings, more or less operation steps or structures may be included in the methods or devices based on conventional or creative efforts. In the steps or structures that logically do not have a necessary causal relationship, the execution order of these steps or the module structure of the device is not limited to the execution order or structure shown in the embodiments of the present application or the drawings.

Specifically, as shown in Figure 1, an embodiment of a method for preparing a GaN-based HEMT device provided by the present application may include:

S1: epitaxially grow a buffer layer, a channel layer, and a barrier layer sequentially on a pre-selected substrate.

FIG. 3 is a schematic structural view during the preparation process of the device obtained in this step. It can be seen from FIG. 3 that a two-dimensional electron gas is formed between the channel layer and the barrier layer.

Wherein, the type of the substrate may include a silicon substrate, a silicon carbide substrate, and a sapphire substrate.

The composition material of the buffer layer includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer includes gallium nitride, and the composition material of the barrier layer includes aluminum gallium nitride.

S2: Depositing a passivation layer on the barrier layer.

Fig. 4 is a schematic structural diagram during the preparation process of the device obtained in this step. In this example, the composition material of the passivation layer includes silicon dioxide or silicon nitride. At the same time, a convex isolation is formed between the passivation layer and the barrier layer by etching or ion implantation.

S3: Etching the passivation layer and a part of the barrier layer to form a groove, and the groove penetrates through the passivation layer and stops at the barrier layer.

In this example, the manner of etching a part of the passivation layer and the barrier layer may include:

A part of the passivation layer and the barrier layer is etched by using a p-type gallium nitride gate mask.

FIG. 5 is a schematic structural view during the preparation process of the device obtained in this step. As shown in FIG. 5 , the p-type gallium nitride gate mask is used for etching, and the formed white area represents the groove, and the bottom of the groove is in the barrier layer.

S4: Regrowing p-type GaN in the groove by using a vapor phase epitaxy growth process, so that the p-type GaN fills the groove.

FIG. 6 is a schematic structural diagram during the preparation process of the device obtained in this step. As shown in FIG. 6 , p-type gallium nitride is regrown in the groove by vapor phase epitaxial growth process, and the p-type gallium nitride fills the groove and protrudes from the groove.

S5: Forming a first source and a first drain on both sides of the p-type gallium nitride respectively, and both the first source and the first drain are plugged into the channel layer.

S6: forming a second source and a second drain on a side of the first drain away from the p-type gallium nitride.

FIG. 7 is a schematic structural diagram during the preparation process of the device obtained in this step. As shown in FIG. 7 , both the first source and the first drain are plugged into the channel layer to form an ohmic contact with the channel layer. Both the second source and the second drain are plugged into the channel layer to form an ohmic contact with the channel layer.

S7: forming a first gate on the p-type GaN, and forming a Schottky contact with the p-type GaN.

Fig. 8 is a schematic structural diagram during the preparation process of the device obtained in this step. As shown in FIG. 8 , the first gate is formed on the p-type GaN to form a Schottky contact with the p-type GaN.

S8: forming a second gate between the second source and the second drain, the second gate forming a Schottky contact with the barrier layer.

FIG. 2 is a schematic structural diagram of a GaN-based HEMT device prepared by using the method described in an embodiment of the present application. The black dotted line in Fig. 2 represents the distribution range of the two-dimensional electron gas 9. It can be seen from the figure that the two-dimensional electron gas is depleted right below the p-type gallium nitride 6, and the two-dimensional electron gas is depleted directly under the second grid. A two-dimensional electron gas 9 exists below. In this way, a normally-off GaN-based HEMT device and a normally-on GaN-based HEMT device are fabricated on the same wafer.

Using the implementation of a GaN-based HEMT device provided in the above embodiments, a normally-on GaN-based HEMT device and a normally-off GaN-based HEMT device can be fabricated on the same wafer. The normally-on HEMT device can be guaranteed to have an optimized barrier structure during epitaxial growth, thereby ensuring its better electrical performance, and the gate threshold voltage of the normally-off HEMT device can be greater than 1V by using the pre-epitaxial growth process.

FIG. 2 is a schematic structural diagram of a GaN-based HEMT device provided by an embodiment of the present application. Specifically, as shown in Figure 2, an embodiment of a GaN-based HEMT device provided by the present application may include:

substrate1;

a buffer layer 2 formed on the substrate 1;

Gallium nitride channel layer 3, epitaxially grown on the buffer layer 2;

an aluminum gallium nitride barrier layer 4 epitaxially grown on the gallium nitride channel layer 3;

a passivation layer 5 deposited on the aluminum gallium nitride barrier layer 4;

The p-type gallium nitride layer 6 runs through a part of the passivation layer 5 and the aluminum gallium nitride barrier layer 4, and the bottom of the p-type gallium nitride layer 6 is located in the aluminum gallium nitride barrier layer 4 in;

A first gate 71 is formed on the p-type gallium nitride layer 6;

Both sides of the first gate 71 are respectively formed with a first source 72 and a first drain 73, and both the first source 72 and the first drain 73 are plugged into the channel layer 3 ;

A second source 82 and a second drain 83 are formed on the side of the first drain 73 away from the first gate 71, and the second source 82 and the second drain 83 are plugged into to the channel layer 3;

A second gate 81 is formed between the second source 82 and the second drain 83;

A two-dimensional electron gas 9 is formed between the channel layer 3 and the barrier layer 4 , and the two-dimensional electron gas in the area directly below the p-type gallium nitride 6 is depleted. That is, there is no two-dimensional electron gas.

In this example, the substrate 1, the buffer layer 2, the barrier layer 4, the channel layer 3, the passivation layer 5, the p-type gallium nitride layer 6, the first A gate 71, the first source 72, and the first drain 73 form a normally closed HEMT device;

The buffer layer 2, the barrier layer 4, the channel layer 3, the passivation layer 5, the second gate 81, the second source 82, the second drain 83 A normally-on HEMT device is formed.

In this example, the first gate 71 forms a Schottky contact with the p-type GaN layer 6, and the second gate 72 forms a Schottky contact with the AlGaN barrier layer 4 .

In this example, the first source 72 and the first drain 73 form an ohmic contact with the channel layer 3, and the second source 82 and the second drain 83 form an ohmic contact with the channel layer 3. Layer 3 forms an ohmic contact.

In this example, the types of the substrate 1 include silicon substrates, silicon carbide substrates, and sapphire substrates;

The composition material of the buffer layer 2 includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer 3 includes gallium nitride, and the composition material of the barrier layer 4 includes aluminum gallium nitride;

The composition material of the passivation layer 5 includes silicon dioxide or silicon nitride.

In an embodiment of the present application, a convex isolation formed by ion implantation or etching is provided between the barrier layer 4 and the passivation layer 5 .

Using the implementation of a gallium nitride-based HEMT device provided in the above embodiment, the device includes a normally-on HEMT device and a normally-closed HEMT device, and the two devices are grown on the same wafer, which can effectively increase the number of devices scope of application. At the same time, it can also ensure that both the normally-on HEMT device and the normally-closed HEMT device have optimal electrical performance.

Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments.

Although the present application has been described by way of example, those of ordinary skill in the art know that there are many variations and changes in the application without departing from the spirit of the application, and it is intended that the appended claims cover these variations and changes without departing from the spirit of the application.

Claims (10)

1. A method for preparing a GaN-based HEMT device, characterized in that the method comprises: Epitaxial growth of buffer layer, channel layer, and barrier layer in sequence on a pre-selected substrate; depositing a passivation layer on the barrier layer; etching a portion of the passivation layer and the barrier layer to form a groove, the groove penetrating through the passivation layer and stopping at the barrier layer; Regrowing p-type gallium nitride in the groove by using a vapor phase epitaxy growth process, so that the p-type gallium nitride fills the groove; A first source and a first drain are respectively formed on both sides of the p-type gallium nitride, and both the first source and the first drain are plugged into the channel layer; forming a second source and a second drain on a side of the first drain away from the p-type gallium nitride; forming a first gate on the p-type gallium nitride, and forming a Schottky contact with the p-type gallium nitride; A second gate is formed between the second source and the second drain, and the second gate forms a Schottky contact with the barrier layer. 2. the preparation method of a kind of GaN-based HEMT device as claimed in claim 1, is characterized in that, the kind of described substrate comprises silicon substrate, silicon carbide substrate, sapphire substrate; The composition material of the buffer layer includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer includes gallium nitride, and the composition material of the barrier layer includes aluminum gallium nitride; The composition material of the passivation layer includes silicon dioxide or silicon nitride. 3. The method for preparing a GaN-based HEMT device according to claim 1, wherein said depositing and forming a passivation layer on said barrier layer comprises: After the convex isolation is formed on the barrier layer by etching or ion implantation, the passivation layer is deposited on the barrier layer to form the passivation layer. 4. The method for preparing a GaN-based HEMT device according to claim 1, wherein said etching a part of said passivation layer and said barrier layer comprises: A part of the passivation layer and the barrier layer is etched by using a p-type gallium nitride gate mask. 5. A GaN-based HEMT device, characterized in that the device comprises: Substrate; a buffer layer formed on the substrate; a gallium nitride channel layer epitaxially grown on said buffer layer; an aluminum gallium nitride barrier layer epitaxially grown on the gallium nitride channel layer; a passivation layer deposited on the aluminum gallium nitride barrier layer; a p-type gallium nitride layer passing through the passivation layer and a part of the aluminum gallium nitride barrier layer, the bottom of the p-type gallium nitride layer being located in the aluminum gallium nitride barrier layer; A first gate is formed on the p-type gallium nitride layer; A first source and a first drain are respectively formed on both sides of the first gate, and both the first source and the first drain are plugged into the channel layer; A second source and a second drain are formed on the side of the first drain away from the first gate, and both the second source and the second drain are plugged into the channel layer ; A second gate is formed between the second source and the second drain; A two-dimensional electron gas is formed between the channel layer and the potential barrier layer, and the two-dimensional electron gas in the region directly below the p-type gallium nitride is depleted. 6. A GaN-based HEMT device according to claim 5, wherein the substrate, the buffer layer, the barrier layer, the channel layer, the passivation layer, The p-type gallium nitride layer, the first gate, the first source, and the first drain form a normally-off HEMT device; The buffer layer, the barrier layer, the channel layer, the passivation layer, the second gate, the second source, and the second drain form a normally-on HEMT device. 7. A gallium nitride-based HEMT device according to claim 5, wherein the first gate forms a Schottky contact with the p-type gallium nitride layer, and the second gate forms a Schottky contact with the p-type gallium nitride layer. The AlGaN barrier layer forms a Schottky contact. 8. A GaN-based HEMT device according to claim 5, wherein the first source and the first drain form an ohmic contact with the channel layer, and the second source electrode and the second drain form ohmic contacts with the channel layer. 9. A gallium nitride-based HEMT device as claimed in claim 5, wherein the type of the substrate comprises a silicon substrate, a silicon carbide substrate, and a sapphire substrate; The composition material of the buffer layer includes gallium nitride or aluminum gallium nitride, the composition material of the channel layer includes gallium nitride, and the composition material of the barrier layer includes aluminum gallium nitride; The composition material of the passivation layer includes silicon dioxide or silicon nitride. 10 . The GaN-based HEMT device according to claim 5 , wherein a convex isolation formed by ion implantation or etching is provided between the barrier layer and the passivation layer. 11 .