SILICON CARBIDE SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE
First Claim
1. A silicon carbide semiconductor device comprising:
- a drift layer having a first conductivity type and made of silicon carbide;
a base region having a second conductivity type and selectively formed in a superficial layer of said drift layer;
a source region having the first conductivity type and selectively formed in a superficial layer of said base region;
a source electrode selectively formed on said source region;
a gate insulating film formed so as to extend over said drift layer, said base region, and an area of said source region where said source electrode is not formed; and
a gate electrode formed on said gate insulating film,said source region including a first source region and a second source region, said first source region being arranged below said source electrode, said second source region being arranged below said gate electrode and formed so as to surround said first source region in a plan view,a doping concentration in a superficial layer of said second source region being lower than a doping concentration in a superficial layer of said first source region,a doping concentration in said second source region being higher in a deep portion than in a superficial portion thereof.
1 Assignment
0 Petitions
Accused Products
Abstract
A silicon carbide semiconductor device that is able to increase the gate reliability, and to provide a method for manufacturing the silicon carbide semiconductor device, and that includes: a source electrode selectively formed on a source region; a gate insulating film formed so as to extend over the source region; and a gate electrode formed on the gate insulating film. The source region includes a first source region located below the source electrode, and a second source region surrounding the first source region. The doping concentration in a superficial layer of the second source region is lower than the doping concentration in a superficial layer of the first source region. The doping concentration in the second source region is higher in a deep portion than in a superficial portion thereof.
-
Citations
9 Claims
-
1. A silicon carbide semiconductor device comprising:
-
a drift layer having a first conductivity type and made of silicon carbide; a base region having a second conductivity type and selectively formed in a superficial layer of said drift layer; a source region having the first conductivity type and selectively formed in a superficial layer of said base region; a source electrode selectively formed on said source region; a gate insulating film formed so as to extend over said drift layer, said base region, and an area of said source region where said source electrode is not formed; and a gate electrode formed on said gate insulating film, said source region including a first source region and a second source region, said first source region being arranged below said source electrode, said second source region being arranged below said gate electrode and formed so as to surround said first source region in a plan view, a doping concentration in a superficial layer of said second source region being lower than a doping concentration in a superficial layer of said first source region, a doping concentration in said second source region being higher in a deep portion than in a superficial portion thereof. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A silicon carbide semiconductor device comprising:
-
a drift layer having a first conductivity type and made of silicon carbide; a base region having a second conductivity type and selectively formed in a superficial layer of said drift layer; a source region selectively formed in a superficial layer of said base region; a source electrode selectively formed on said source region; a gate insulating film formed so as to extend over said drift layer, said base region, and an area of said source region where said source electrode is not formed; and a gate electrode formed on said gate insulating film, said source region including an upper-layer region and a lower-layer region, said upper-layer region having the second conductivity type and formed in a superficial portion, said lower-layer region having the first conductivity type and formed in a lower layer below said upper-layer region, said source electrode having a lower end thereof buried in said source region so as to reach said lower-layer region. - View Dependent Claims (7)
-
-
8. A method for manufacturing a silicon carbide semiconductor device, said method comprising the steps of:
-
(a) forming a drift layer having a first conductivity type and made of silicon carbide; (b) selectively forming a base region in a superficial layer of said drift layer, said base region having a second conductivity type; (c) selectively forming a source region in a superficial layer of said base region, said source region having the first conductivity type and including a first source region and a second source region that is formed so as to surround said first source region in a plan view; (d) forming a gate insulating film so as to extend over said drift layer, said base region, and said source region; (e) forming a gate electrode on said gate insulating film such that said gate electrode extends from the superficial layer of said drift layer to a superficial layer of said second source region; and (f) etching and removing a portion of said gate insulating film at a position corresponding to said first source region, and forming a source electrode on said first source region, a doping concentration in the superficial layer of said second source region being lower than a doping concentration in a superficial layer of said first source region, a doping concentration in said second source region being higher in a deep portion than in a superficial portion thereof.
-
-
9. A method for manufacturing a silicon carbide semiconductor device, said method comprising the steps of:
-
(a) forming a drift layer having a first conductivity type and made of silicon carbide; (b) selectively forming a base region in a superficial layer of said drift layer, said base region having a second conductivity type; (c) selectively forming a source region in a superficial layer of said base region, said source region including an upper-layer region having the second conductivity type and formed in a superficial portion and a lower-layer region having the first conductivity type and formed in a lower layer below said upper-layer region; (d) forming a gate insulating film so as to extend over said drift layer, said base region, and said source region; (e) forming a gate electrode on said gate insulating film such that said gate electrode extends from the superficial layer of said drift layer into a superficial layer of said source region; (f) forming a trench that extends from an area of a surface of said gate insulating film where said gate electrode is not formed and reaches said lower-layer region; and (g) forming a source electrode such that a lower end thereof is buried in said trench.
-
Specification