Silicon carbide semiconductor device

• US 8,525,223 B2
• Filed: 04/19/2012
• Issued: 09/03/2013
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Watanabe, Hiroki, Miyahara, Shinichiro, Sugimoto, Masahiro, Takaya, Hidefumi, Watanabe, Yukihiko, Soejima, Narumasa, Ishikawa, Tsuyoshi
• Primary Examiner(s): Lebentritt, Michael
• Application Number:
  US13/450,639
• Publication Number:
  US 20120273801A1
• Time in Patent Office: 502 Days
• Field of Search: 257130-135, 257/301, 257/330, 257/341, 257/E21.041, 257/29.084, 257/104, 257243-262, 257/313, 257/346
• US Class Current: 257/130
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/66068 the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A SiC semiconductor device includes: a SiC substrate including a first or second conductive type layer and a first conductive type drift layer and including a principal surface having an offset direction; a trench disposed on the drift layer and having a longitudinal direction; and a gate electrode disposed in the trench via a gate insulation film. A sidewall of the trench provides a channel formation surface. The vertical semiconductor device flows current along with the channel formation surface of the trench according to a gate voltage applied to the gate electrode. The offset direction of the SiC substrate is perpendicular to the longitudinal direction of the trench.

Claims

1. A silicon carbide semiconductor device having a vertical semiconductor element with a trench gate structure comprising:

a silicon carbide semiconductor substrate including a first or second conductive type layer and a drift layer on the first or second conductive type layer, wherein the drift layer has the first conductive type, and the silicon carbide semiconductor substrate includes a principal surface having an offset direction;

a trench disposed on a surface of the drift layer and having a longitudinal direction; and

a gate electrode disposed in the trench via a gate insulation film,

wherein a sidewall of the trench provides a channel formation surface,

wherein the vertical semiconductor device is configured to flow current along with the channel formation surface of the trench according to a gate voltage applied to the gate electrode, and

wherein the offset direction of the silicon carbide semiconductor substrate is perpendicular to the longitudinal direction of the trench.

2. The silicon carbide semiconductor device according to claim 1,

wherein the principal surface of the silicon carbide semiconductor substrate is a silicon-plane,

wherein the offset direction of the silicon carbide semiconductor substrate is a <

11−

20>

-direction, and

wherein the longitudinal direction of the trench is a <

1−

100>

-direction.

3. The silicon carbide semiconductor device according to claim 1,

wherein the principal surface of the silicon carbide semiconductor substrate is a silicon-plane,

wherein the offset direction of the silicon carbide semiconductor substrate is a <

1−

100>

-direction, and

wherein the longitudinal direction of the trench is a <

11−

20>

-direction.

4. The silicon carbide semiconductor device according to claim 1,

wherein the principal surface of the silicon carbide semiconductor substrate is a carbon-plane,

wherein the offset direction of the silicon carbide semiconductor substrate is a <

11−

20>

-direction, and

wherein the longitudinal direction of the trench is a <

1−

100>

-direction.

5. The silicon carbide semiconductor device according to claim 1,

wherein the principal surface of the silicon carbide semiconductor substrate is a carbon-plane,

wherein the offset direction of the silicon carbide semiconductor substrate is a <

1−

100>

-direction, and

wherein the longitudinal direction of the trench is a <

11−

20>

-direction.

6. The silicon carbide semiconductor device according to claim 1, further comprising:

a drain electrode disposed on the first or second conductive type layer opposite to the drift layer;

a base region disposed in a surface portion of the drift layer;

a source region disposed in a surface portion of the base region;

a contact layer disposed in another surface portion of the base region adjacent to the source region; and

a source electrode disposed on the source region and the contact layer so that the source electrode is electrically coupled with the source region and the contact layer,

wherein the trench penetrates the source region and the base region, and reaches the drift layer, and

wherein contact layer is disposed on both sides of the trench via the source region.

7. The silicon carbide semiconductor device according to claim 6, further comprising:

a deep layer disposed in the drift layer under the base region,

wherein the deep layer contacts the base region, and

wherein the deep layer has an extending direction, which is perpendicular to the longitudinal direction of the trench.