CN111192874A

CN111192874A - GaN power device with composite structure

Info

Publication number: CN111192874A
Application number: CN202010030167.8A
Authority: CN
Inventors: 王磊
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-01-13
Filing date: 2020-01-13
Publication date: 2020-05-22

Abstract

The invention discloses a GaN power device with a composite structure, comprising a GaN field effect transistor (GaN FET) and a GaN Schottky diode (GaN SBD), wherein the GaN SBD is located between the gate electrode and the source electrode of the GaN FET; The anode of the GaN SBD is electrically connected to the source of the GaN FET, and the cathode of the GaN SBD is electrically connected to the gate of the GaN FET. The invention can effectively avoid the device failure caused by the instantaneous surge voltage during the application process of the device, and improve the reliability of the device.

Description

GaN power device with composite structure

Technical Field

The invention belongs to the technical field of power semiconductor devices, and particularly relates to a high-reliability GaN power device with a composite structure.

Background

The semiconductor power device is a core element of a power electronic system, and the emergence of each new generation of power electronic devices is accompanied with a revolution of technical innovation. At present, the MOSFET made of Si material plays a great role in the application of semiconductor power devices and occupies the leading position of the market. However, due to the limitation of Si materials, although the performance of Si material MOSFETs is continuously improved through various processes, materials and design optimization, the improvement is far behind the development speed of power electronic technology, Si material power semiconductor devices have been unable to meet the requirements of rapidly developed power systems on high frequency, low power consumption, high power capacity and the like, and new generation wide bandgap power semiconductor materials and devices represented by GaN are gradually developed to meet the requirements of new generation power systems.

At present, a conventional GaN power device is of a planar transverse structure, the device is mainly divided into two main types of depletion mode (D-mode) and enhancement mode (E-mode), the research of the two types of depletion mode (D-mode) and enhancement mode (E-mode) is in a starting stage, the design structure and the technical route are various, and the main design structure comprises: a trench gate (access gate) design structure, a p-GaN gate design structure, a gate Injection transistor (git) design structure of the japan patent proprietary to Panasonic, and an island technology design structure of the canadian GaN Systems patent proprietary. However, the intrinsic stress caused by the conventional GaN power device material structure, the interface state density of the MIS gate structure is high, and the stability of the passivation layer grown on the surface of the AlGaN barrier layer is poor, so that the gate reliability of the device is poor. Therefore, on one hand, the intrinsic stress of the material is reduced, the process level of the device is improved, on the other hand, the design structure of the device is optimized, the protection of the grid electrode of the device is enhanced, and the method is an important method for improving the reliability of the GaN power device.

Disclosure of Invention

The invention mainly aims to provide a GaN power device with a composite structure, which can effectively improve the reliability of the device.

In order to achieve the purpose, the invention adopts a technical scheme that: provided is a GaN power device of a composite structure, including: a substrate; an AlN nucleation layer formed on the substrate; a GaN buffer layer formed on the AlN nucleation layer; a GaN channel layer formed on the GaN buffer layer; an AlGaN barrier layer formed on the GaN channel layer; the passivation layer is formed on the AlGaN barrier layer, and the bottom end of the passivation layer is at least partially embedded into the GaN channel layer; the drain electrode is formed on the AlGaN barrier layer of the drain electrode region, and the bottom end of the drain electrode is embedded into the AlGaN barrier layer; the source electrode is formed on the AlGaN barrier layer of the source electrode region, and the bottom end of the source electrode is embedded into the AlGaN barrier layer; a gate formed on the passivation layer over the AlGaN barrier layer; the cathode is formed on the AlGaN barrier layer of the cathode region, and the bottom end of the cathode is embedded into the AlGaN barrier layer; an anode formed on the AlGaN barrier layer; a gate lead-out metal formed on the gate; a first common wiring layer extending from the source electrode to the anode electrode, wherein the source electrode and the anode electrode are electrically connected to each other via the first common wiring layer; a first interlayer insulating film formed on the passivation layer between the source electrode and the anode electrode; a second common wiring layer extending from the gate electrode to the cathode electrode, wherein the gate electrode and the cathode electrode are electrically connected to each other via the second common wiring layer; a second layer insulating film formed on the passivation layer and the first common wiring layer.

Preferably, the substrate is made of Si, SiC, GaN or Al₂O₃。

Preferably, the source, drain and cathode and the AlGaN barrier layer form an alloy ohmic contact.

Preferably, the anode forms a schottky contact with the AlGaN barrier layer.

Preferably, the material adopted by the passivation layer is Si₃N₄、HfO₂Or Al₂O₃。

Preferably, the cathode forms a GaN schottky diode (GaNSBD) with the anode and the AlGaN barrier layer.

Preferably, the drain, the gate and the source and the AlGaN barrier layer form a GaN field effect transistor (GaN FET).

The GaN SBD integrated in parallel connection between the grid electrode and the source electrode of the GaN power device with the composite structure can effectively clamp the voltage between the grid electrode and the source electrode, control the voltage between the grid electrode and the source electrode and improve the reliability of the device.

Drawings

FIG. 1 is a schematic diagram of a composite structure GaN power device according to an embodiment of the invention;

fig. 2 is an equivalent circuit diagram of the device disclosed by the invention.

Detailed Description

The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

A GaN power device with a composite structure according to an embodiment of the present invention, as shown in fig. 1, includes a substrate 1, an AlN nucleation layer 2, a GaN buffer layer 3, a GaN channel layer 4, an AlGaN barrier layer 5, a passivation layer 6, a cathode 7, a drain 8, a source 9, an anode 10, a gate 11, a first interlayer insulating film 12, a first common wiring layer 13, a second layer insulating film 14, a drain extraction metal 15, and a second common wiring layer 16.

Wherein an AlN nucleation layer 2 is formed on a substrate 1. A GaN buffer layer 3 is formed on the AlN nucleation layer 2. The GaN channel layer 4 is formed on the GaN buffer layer 3. The AlGaN barrier layer 5 is formed on the GaN channel layer 4. A passivation layer 6 is formed on the AlGaN barrier layer 5, and a bottom end of the passivation layer 6 is at least partially embedded inside the GaN channel layer 4. The drain 8 is formed on the AlGaN barrier layer 5 in the drain region, and the bottom end of the drain 8 is embedded inside the AlGaN barrier layer 5. The source 9 is formed on the AlGaN barrier layer 5 in the source region, and the bottom end of the source 9 is embedded inside the AlGaN barrier layer 5. A gate 11 is formed on the passivation layer 6 above the AlGaN barrier layer 5. The cathode 7 is formed on the AlGaN barrier layer 5 in the cathode region, and the bottom end of the cathode 7 is embedded inside the AlGaN barrier layer 5. The anode 10 is formed on the AlGaN barrier layer 5. A drain lead metal 15 is formed on the gate electrode 11. The first common wiring layer 13 extends from the source 9 to the anode 10, wherein the source 9 and the anode 10 are electrically connected to each other via the first common wiring layer 13. A first interlayer insulating film 12 is formed on the passivation layer 6 between the source electrode 9 and the anode electrode 10. The second common wiring layer 16 extends from the gate electrode 11 to the cathode electrode 7, wherein the gate electrode 11 and the cathode electrode 7 are electrically connected to each other via the second common wiring layer 16. A second-layer insulating film 14 is formed on the passivation layer 6 and the first common wiring layer 13.

In the present embodiment, the material used for the substrate 1 is Si, SiC, GaN or Al₂O₃. The source electrode 9 and the drain electrode 8 form alloy ohmic contacts with the cathode 7 and the AlGaN barrier layer 5. The anode 10 forms a schottky contact with the AlGaN barrier layer 5. The passivation layer 6 is made of Si₃N₄、HfO₂Or Al₂O₃. The cathode 7 forms a GaN schottky diode (GaNSBD) with the anode 10 and the AlGaN barrier layer 5. The drain 8, gate 11 and source 9 and AlGaN barrier layer 5 form a GaN field effect transistor (GaN FET).

The AlGaN barrier layer 5 and the GaN channel layer 4 form an AlGaN/GaN heterojunction, and two-dimensional electron gas (2 DEG) is generated at an interface of the heterojunction, and the 2DEG is a conductive carrier, as shown by a dotted line in fig. 1.

As can be seen from fig. 1, a groove is formed between the source 9 and the anode 10, electrically isolating the GaN SBD and the GaN FET from each other.

The GaNSBD integrated in parallel connection between the grid electrode and the source electrode of the GaN power device with the composite structure can effectively clamp the voltage between the grid electrode and the source electrode, control the voltage between the grid electrode and the source electrode, and improve the reliability of the device.

While the invention has been described in detail with respect to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. a GaN power device of composite structure, is characterized in that, comprises:

substrate;

An AlN nucleation layer formed on the substrate;

a GaN buffer layer formed on the AlN nucleation layer;

a GaN channel layer formed on the GaN buffer layer;

AlGaN barrier layer, the AlGaN barrier layer is formed on the GaN channel layer;

a passivation layer, the passivation layer is formed on the AlGaN barrier layer, and the bottom end of the passivation layer is at least partially embedded inside the GaN channel layer;

a drain, the drain is formed on the AlGaN barrier layer in the drain region, and the bottom end of the drain is embedded in the AlGaN barrier layer;

a source electrode, the source electrode is formed on the AlGaN barrier layer in the source region, and the bottom end of the source electrode is embedded inside the AlGaN barrier layer;

a gate, which is formed on the passivation layer above the AlGaN barrier layer;

a cathode, the cathode is formed on the AlGaN barrier layer in the cathode region, and the bottom end of the cathode is embedded in the AlGaN barrier layer;

an anode formed on the AlGaN barrier layer;

a drain extraction metal, the gate extraction metal is formed on the gate;

a first common wiring layer extending from the source to the anode, wherein the source and the anode are electrically connected to each other via the first common wiring layer;

a first interlayer insulating film, the first interlayer insulating film is formed on the passivation layer between the source electrode and the anode;

a second common wiring layer extending from the gate to the cathode, wherein the gate and the cathode are electrically connected to each other via the second common wiring layer;

A second insulating film is formed on the passivation layer and the first common wiring layer.

2 . The GaN power device with a composite structure according to claim 1 , wherein the material used for the substrate is Si, SiC, GaN or Al ₂ O ₃ . 3 .

3 . The GaN power device with a composite structure according to claim 1 , wherein the source electrode, the drain electrode and the cathode electrode and the AlGaN barrier layer form an alloy ohmic contact. 4 .

4 . The GaN power device with a composite structure according to claim 1 , wherein the anode forms a Schottky contact with the AlGaN barrier layer. 5 .

5 . The GaN power device with a composite structure according to claim 1 , wherein the material used for the passivation layer is Si ₃ N ₄ , HfO ₂ or Al ₂ O ₃ . 6 .

6 . The GaN power device with a composite structure according to claim 1 , wherein the cathode, the anode and the AlGaN barrier layer form a GaN Schottky diode (GaN SBD). 7 .

7 . The GaN power device with a composite structure according to claim 1 , wherein the drain electrode, the gate electrode, the source electrode and the AlGaN barrier layer form a GaN field effect transistor. 8 . (GaN FET).