Silicon carbide semiconductor device and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11049966-B2
Application number	US-202016997210-A
Country	US
Kind code	B2
Filing date	Aug 19, 2020
Priority date	Aug 31, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

When a film thickness of a second epitaxial film is measured, an infrared light is irradiated from a surface side of the second epitaxial film onto a base layer on which a first epitaxial film and the second epitaxial film are formed. A reflected light from an interface between the first epitaxial film and the base layer and a reflected light from a surface of the second epitaxial film are measured to obtain a two-layer film thickness, which is a total film thickness of the first epitaxial film and the second epitaxial film. The film thickness of the second epitaxial film is calculated by subtracting a one-layer film thickness, which is a film thickness of the first epitaxial film, from the two-layer film thickness.

First claim

What is claimed is:

1. A silicon carbide semiconductor device comprising a vertical MOSFET that includes:
a substrate forming a base layer and made of silicon carbide of a first conductivity type or a second conductivity type;
a drift layer formed on the substrate and made of an epitaxial film of silicon carbide of the first conductivity type;
a base region formed on the drift layer and made of an epitaxial film of silicon carbide of the second conductivity type;
a source region formed on an upper layer portion of the base region and made of silicon carbide of the first conductivity type having a higher impurity concentration than an impurity concentration of the drift layer;
a trench gate structure formed in a gate trench formed deeper than the base region from a surface of the source region, and including a gate insulating film formed on an inner wall surface of the gate trench and a gate electrode formed on the gate insulating film;
a source electrode electrically connected to the source region; and
a drain electrode electrically connected to a rear surface of the substrate,
wherein
a film thickness of the drift layer is set to 5 μm to 14 μm, a film thickness of the base region is set to 0.5 μm to 2.0 μm, and an amount of protrusion of the gate trench from a bottom of the base region is set to 0.2 μm to 0.4 μm.

2. The silicon carbide semiconductor device according to claim 1 , wherein
the source region is made of an epitaxial film, and a total film thickness of the drift layer, the base region, and the source region is set to 5 μm to 16 μm.

3. The silicon carbide semiconductor device according to claim 1 , further comprising:
a trench deeper than the gate trench and formed in the drift layer; and
a deep layer of the second conductivity type disposed in the trench.

4. The silicon carbide semiconductor device according to claim 1 , wherein
the film thickness of the drift layer is set to 5 μm to 10 μm,
a total film thickness of the drift layer and the base region is set to 5 μm to 10 μm, and
a total film thickness of the drift layer, the base region, and the source region is set to 5 μm to 10 μm.

Assignees

• Denso Corp
• Toyota Motor Co Ltd

Inventors

• Amano Akira
• SATOMURA Takayuki
• Takeuchi Yuichi
• Suzuki Katsumi
• Aoi Sachiko

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P30/204

  into Group IV semiconductors · CPC title

• H10P30/21

  of electrically active species · CPC title

• H10D62/8325

  Silicon carbide · CPC title