Semiconductor device and semiconductor device manufacturing method

Patent metadata

Field	Value
Publication number	US-8987812-B2
Application number	US-201013203341-A
Country	US
Kind code	B2
Filing date	Jan 6, 2010
Priority date	Mar 30, 2009
Publication date	Mar 24, 2015
Grant date	Mar 24, 2015

Abstract

The invention provides an ultra-low-on-resistance, excellent-reliability semiconductor device that can finely be processed using SiC and a semiconductor device producing method. A semiconductor device includes: a silicon carbide substrate; a first-conductive-type first silicon carbide layer provided on a first principal surface of the silicon carbide substrate; a second-conductive-type first silicon carbide region formed at a surface of the first silicon carbide layer; a first-conductive-type second silicon carbide region formed at a surface of the first silicon carbide region; a second-conductive-type third silicon carbide region formed below the second silicon carbide region; a trench piercing through the second silicon carbide region to reach the third silicon carbide region; a gate insulating film; a gate electrode; an interlayer insulating film with which the gate electrode is covered; a first electrode that is formed on the second silicon carbide region and the interlayer insulating film in a side surface of the trench while containing a metallic element selected from a group consisting of Ni, Ti, Ta, Mo, and W; a second electrode that is formed on the third silicon carbide region in a bottom portion of the trench and the first electrode while containing Al; a first main electrode formed on the second electrode; and a second main electrode formed on a second principal surface of the silicon carbide substrate.

First claim

The invention claimed is:

1. A semiconductor device comprising:
a silicon carbide substrate that has first and second principal surfaces;
a first-conductive-type first silicon carbide layer that is provided on the first principal surface of the silicon carbide substrate;
a second-conductive-type first silicon carbide region that is formed at a surface of the first silicon carbide layer;
a first-conductive-type second silicon carbide region that is formed at a surface of the first silicon carbide region;
a second-conductive-type third silicon carbide region that is formed below the second silicon carbide region;
a trench that is formed so as to pierce through the second silicon carbide region to reach the third silicon carbide region;
a gate insulating film that is continuously formed on surfaces of the second silicon carbide region, the first silicon carbide region, and the first silicon carbide layer;
a gate electrode that is formed on the gate insulating film;
an interlayer insulating film with which the gate electrode is covered;
a first electrode that is formed directly on the second silicon carbide region and the interlayer insulating film on a side surface of the trench while containing a metallic element selected from a group consisting of Ni, Ti, Ta, Mo, and W;
a second electrode that is formed directly on the third silicon carbide region in a bottom portion of the trench and on the first electrode while containing Al;
a first main electrode that is formed on the second electrode; and
a second main electrode that is formed on the second principal surface of the silicon carbide substrate.

2. The semiconductor device according to claim 1 , wherein the interlayer insulating film is a silicon oxide film.

3. The semiconductor device according to claim 2 , wherein a sidewall insulating film formed by a silicon nitride film is sandwiched between the interlayer insulating film and the first electrode.

4. The semiconductor device according to claim 1 , wherein the silicon carbide substrate is the first conductive type and the device is a MOSFET.

5. The semiconductor device according to claim 1 , wherein the silicon carbide substrate is the second conductive type and the device is an IGBT.

6. A semiconductor device comprising:
a silicon carbide substrate that has first and second principal surfaces;
a first-conductive-type first silicon carbide layer that is provided on the first principal surface of the silicon carbide substrate;
a second-conductive-type first silicon carbide region that is formed at a surface of the first silicon carbide layer;
a first-conductive-type second silicon carbide region that is formed at a surface of the first silicon carbide region;
a second-conductive-type third silicon carbide region that is selectively formed in the first silicon carbide region;
a first trench that is formed so as to pierce through the second silicon carbide region and the first silicon carbide region to reach the first silicon carbide layer;
an insulator that is formed in a bottom portion of the first trench;
a gate insulating film that is continuously formed on surfaces of the second silicon carbide region, the first silicon carbide region, and the first silicon carbide layer on a side surface of the first trench;
a gate electrode that is formed on the gate insulating film;
an interlayer insulating film with which the gate electrode is covered;
a second trench that is formed so as to pierce through the second silicon carbide region to reach the third silicon carbide region;
a first electrode that is formed directly on the second silicon carbide region and the interlayer insulating film on a side surface of the second trench while containing a metallic element selected from a group consisting of Ni, Ti, Ta, Mo, and W;
a second electrode that is formed directly on the third silicon carbide region in a bottom portion of the second trench and on the first electrode while containing Al;
a first main electrode that is formed on the second electrode; and
a second main electrode, that is formed on the second principal surface of the silicon carbide substrate.

7. The semiconductor device according to claim 6 , wherein the interlayer insulating film is a silicon oxide film.

8. The semiconductor device according to claim 7 , wherein a sidewall insulating film formed by a silicon nitride film is sandwiched between the interlayer insulating film and the first electrode.

9. The semiconductor device according to claim 6 , wherein the silicon carbide substrate is the first conductive type and the device is a MOSFET.

10. The semiconductor device according to claim 6 , wherein the silicon carbide substrate is the second conductive type and the device is an IGBT.

Assignees

• Kono Hiroshi
• Shinohe Takashi
• Mizukami Makoto
• Toshiba Kk

Inventors

• Kono Hiroshi
• Shinohe Takashi
• Mizukami Makoto

Classifications

• H10P30/22

  using masks · CPC title

• H10D64/0115

  to silicon carbide · CPC title

• H10D64/516

  the thicknesses being non-uniform · CPC title

• H10D64/256

  for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies (source or drain electrodes of TFTs H10D30/673) · CPC title

• H10D64/62

  Electrodes ohmically coupled to a semiconductor · CPC title