Silicon carbide semiconductor device and method of manufacturing silicon carbide semiconductor device

Patent metadata

Field	Value
Publication number	US-2017194438-A1
Application number	US-201715468941-A
Country	US
Kind code	A1
Filing date	Mar 24, 2017
Priority date	Jan 16, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

A silicon carbide semiconductor device, including a silicon carbide semiconductor structure, an insulated gate structure including a gate insulating film contacting the silicon carbide semiconductor structure and a gate electrode formed on the gate insulating film, an interlayer insulating film covering the insulated gate structure, a metal layer provided on the interlayer insulating film for absorbing or blocking hydrogen, and a main electrode provided on the metal layer and electrically connected to the silicon carbide semiconductor structure.

First claim

What is claimed is:

1 . A silicon carbide semiconductor device, comprising:
a silicon carbide semiconductor structure; an insulated gate structure including
a gate insulating film, which is a silicon dioxide film, contacting the silicon carbide semiconductor structure, and
a gate electrode formed on the gate insulating film;
an interlayer insulating film covering the insulated gate structure; a metal layer provided on the interlayer insulating film for absorbing or blocking hydrogen; and a main electrode provided on the metal layer and electrically connected to the silicon carbide semiconductor structure.

2 . The silicon carbide semiconductor device according to claim 1 , wherein the metal layer is a titanium film.

3 . The silicon carbide semiconductor device according to claim 1 , wherein the metal layer covers an entire top surface of the interlayer insulating film.

4 . The silicon carbide semiconductor device according to claim 1 , wherein the interlayer insulating film covers the insulated gate structure and contacts the gate insulating film.

5 . The silicon carbide semiconductor device according to claim 1 , wherein the main electrode is free of direct contact with the interlayer insulating film and the gate insulating film.

6 . The silicon carbide semiconductor device according to claim 1 , wherein a thickness of the metal layer is 10 nm to 1.0 μm.

7 . The silicon carbide semiconductor device according to claim 6 , wherein the thickness of the metal layer is 80 nm to 150 nm.

8 . The silicon carbide semiconductor device according to claim 1 , wherein the metal layer has an absorbed hydrogen molecule concentration of 1×10 16 /cm 2 or higher.

9 . The silicon carbide semiconductor device according to claim 1 , wherein
the metal layer is a first metal layer, and the silicon carbide semiconductor device further includes a second metal layer provided between the first metal layer and the main electrode, the second metal layer being chemically stable with respect to the first metal layer.

10 . The silicon carbide semiconductor device according to claim 9 , wherein the second metal layer is a titanium nitride film.

11 . The silicon carbide semiconductor device according to claim 9 , further comprising
a third metal layer, provided between the second metal layer and the main electrode, for absorbing or blocking the hydrogen.

12 . The silicon carbide semiconductor device according to claim 11 , wherein the third metal layer is a titanium film.

13 . The silicon carbide semiconductor device according to claim 11 , further comprising
an alloy film provided between the third metal layer and the main electrode, the alloy film containing titanium and aluminum.

14 . The silicon carbide semiconductor device according to claim 1 , further comprising
an alloy film provided between the metal layer and the main electrode, the alloy film containing titanium and aluminum.

15 . The silicon carbide semiconductor device according to claim 14 , wherein a thickness of the alloy film is 10 nm to 50 nm.

16 . The silicon carbide semiconductor device according to claim 1 , wherein
the main electrode is a first main electrode; the silicon carbide semiconductor device further includes
a silicon carbide semiconductor substrate, and
an n-type drift layer and a second main electrode respectively provided on two opposite surfaces of the silicon carbide semiconductor substrate;
the silicon carbide semiconductor structure includes
a p-type semiconductor region selectively formed in the n-type drift layer, and
an n-type semiconductor region selectively provided in the p-type semiconductor region;
the gate insulating film covers a surface of a portion of the p-type semiconductor region between the n-type drift layer and the n-type semiconductor region; and the first main electrode is electrically connected to the n-type semiconductor region.

17 . The silicon carbide semiconductor device according to claim 16 , wherein the silicon carbide semiconductor substrate is of an n-type and has an impurity concentration that is higher than that of the n-type drift layer.

18 . A method of manufacturing a silicon carbide semiconductor device, comprising:
providing a silicon carbide semiconductor base having a silicon carbide semiconductor structure formed thereon; forming an insulated gate structure, including
thermally oxidizing the silicon carbide semiconductor structure to form a silicon dioxide film on a surface thereof, and
forming a gate electrode on the silicon dioxide film;
forming an interlayer insulating film covering the insulated gate structure; forming a titanium film on the interlayer insulating film; and forming on the titanium film a main electrode that is electrically connected to the silicon carbide semiconductor structure.

19 . The method of manufacturing a silicon carbide semiconductor device according to claim 18 , comprising
performing heat treating at a temperature of 450 degrees C. or less after forming the main electrode.

Assignees

• Fuji Electric Co Ltd

Inventors

• Kumagai Naoki
• Tsutsumi Takashi
• Sakai Yoshiyuki
• Oonishi Yasuhiko
• Fujimoto Takumi
• Fukuda Kenji
• Harada Shinsuke
• Okamoto Mitsuo

Classifications

• H10D64/0115 Primary

  to silicon carbide · CPC title

• H01L29/7813

  Electricity · mapped topic

• H01L29/1095

  Electricity · mapped topic

• H01L29/47

  Electricity · mapped topic

• H01L29/66068

  Electricity · mapped topic