Semiconductor device

Patent metadata

Field	Value
Publication number	US-9443937-B2
Application number	US-201514807369-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Sep 19, 2014
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A semiconductor device according to an embodiment includes a SiC layer including a first region provided at a surface. The first region satisfies N A −N D <5×10 15 cm −3 when a concentration of a p-type impurity is denoted by N A , whereas a concentration of an n-type impurity is denoted by N D . The surface is inclined at 0 degrees or more and 10 degrees or less to a {000-1} face, or the surface having a normal direction inclined at 80 degrees or more and 90 degrees or less to a <000-1> direction. The device includes a gate electrode, a gate insulating film provided between the SiC layer and the gate electrode, and a second region provided between the first region and the gate insulating film. The second region has a nitrogen concentration higher than 1×10 22 cm −3 .

First claim

What is claimed is:

1. A semiconductor device comprising:
a SiC layer including a first region provided at a surface, the first region satisfies N A −N D <5×10 15 cm −3 when a concentration of a p-type impurity is denoted by N A , whereas a concentration of an n-type impurity is denoted by N D , the surface being inclined at 0 degrees or more and 10 degrees or less to a {000-1} face, or the surface having a normal direction inclined at 80 degrees or more and 90 degrees or less to a <000-1> direction;
a gate electrode;
a gate insulating film provided between the SiC layer and the gate electrode; and
a second region provided between the first region and the gate insulating film, the second region having a nitrogen concentration higher than 1×10 22 cm −3 .

2. The device according to claim 1 , wherein the first region is n-type.

3. The device according to claim 1 , wherein the first region satisfies N A <5×10 15 cm −3 .

4. The device according to claim 1 , wherein a concentration of aluminum in the first region is less than 5×10 15 cm −3 .

5. The device according to claim 1 , wherein a distance is 10 nm or less from the gate insulating film to a location where the concentration of nitrogen is 1×10 19 cm −3 or less in the second region.

6. The device according to claim 1 , wherein the SiC layer further comprising:
a base region having p-type impurity concentration of 1×10 16 cm −3 or more, the first region provided between the base region and the gate insulating film;
an n-type source region provided at the surface; and
an n-type drift region, the base region provided between the n-type source region and the n-type drift region.

7. The device according to claim 1 , wherein the first region is 20 nm or less in width.

8. The device according to claim 1 , wherein the gate insulating film is a silicon oxide film or a silicon nitride film.

9. The device according to claim 1 , wherein the surface having the normal direction inclined at 80 degrees or more and 90 degrees or less to the <000-1> direction is a surface inclined at 0 degrees or more and 10 degrees or less to a {1-100} face, or a surface inclined at 0 degrees or more and 10 degrees or less to a {11-20} face.

10. The device according to claim 1 , wherein the first region contains nitrogen.

Assignees

• Toshiba Kk

Inventors

• Iijima Ryosuke
• Ohashi Teruyuki
• Shimizu Tatsuo
• Shinohe Takashi

Classifications

• H10D30/668

  having trench gate electrodes, e.g. UMOS transistors · CPC title

• H10D12/031

  of IGBTs · CPC title

• H10D1/66

  Conductor-insulator-semiconductor capacitors, e.g. MOS capacitors · CPC title

• H10D64/693

  the insulator comprising nitrogen, e.g. nitrides, oxynitrides or nitrogen-doped materials · CPC title

• H10D64/685

  being perpendicular to the channel plane · CPC title