Power device

• US 8,129,818 B2
• Filed: 10/14/2008
• Issued: 03/06/2012
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Tooi, Shigeo, Tsunoda, Tetsujiro
• Primary Examiner(s): Nguyen, Thinh T
• Application Number:
  US13/058,544
• Publication Number:
  US 20110133312A1
• Time in Patent Office: 1,239 Days
• Field of Search: 257/586, 257/583, 257/510, 257/E29.201, 438/343, 438/221, 438/296, 438/353
• US Class Current: 257/586
• CPC Class Codes: H01L 29/0661 specially adapted for altering the breakdown voltage by removing semiconductor material at, or in the neighbourhood of, a reverse biased junction, e.g. by bevelling, moat etching, depletion etching
• 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 29/7395 Vertical transistors, e.g. vertical IGBT

Abstract

The present invention is a power device includes, a first conductive type semiconductor substrate, a second conductive type base region formed on a surface of the semiconductor substrate, a second conductive type collector region formed on a rear surface of the semiconductor substrate, a first conductive type emitter region formed on a surface of the base region, a trench gate formed via a gate insulating film in a first trench groove formed in the base region so as to penetrate the emitter region, a dent formed in the base region in proximity to the emitter region, a second conductive type contact layer formed on an inner wall of the dent, having a higher dopant density than that of the base region, a dummy trench formed via a dummy trench insulating film in a second trench groove formed at a bottom of the dent, and an emitter electrode electrically connected to the emitter region, the contact layer and the dummy trench, wherein the trench gate and the dummy trench reach the semiconductor substrate.

Claims

1. A power device comprising:

a first conductive type semiconductor substrate;

a second conductive type base region formed on a surface of the semiconductor substrate;

a second conductive type collector region formed on a rear surface of the semiconductor substrate;

a first conductive type emitter region formed on a surface of the base region;

a trench gate formed via a gate insulating film in a first trench groove formed in the base region so as to penetrate the emitter region;

a dent formed in the base region in proximity to the emitter region;

a second conductive type contact layer formed on an inner wall of the dent, having a higher dopant density than that of the base region;

a dummy trench formed via a dummy trench insulating film in a second trench groove formed at a bottom of the dent; and

an emitter electrode electrically connected to the emitter region, the contact layer and the dummy trench,

wherein the trench gate and the dummy trench reach the semiconductor substrate.

2. The power device according to claim 1, wherein the emitter region is formed even in part of the inner wall of the dent.

3. The power device according to claim 1, wherein a first conductive type carrier storage layer is formed in a region of the semiconductor substrate contacting the base region, and

a dopant density of the carrier storage layer is higher than a dopant density of a region of the semiconductor substrate where the carrier storage layer is not formed.