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US 6,600,192 B1Granted
Vertical field-effect semiconductor device with buried gate region
AssigneeThe Kansai Electric Power Co., Inc.
InventorsYoshitaka Sugawara, Katsunori Asano
Life of this patent
Estimating the term…
Abstract
A buried gate region, a buried gate contact region and a gate contact region are provided on an SiC substrate. Thereby, a depletion layer expands in the channel region, and a high withstand voltage is attained in the normally off state. By applying a voltage of the built-in voltage or less to a gate, the depletion layer in the channel region becomes narrower and an ON-state resistance becomes low. Furthermore, when a voltage of the built-in voltage or more is applied to the gate, holes are injected from the gate so as to cause the conductivity modulation, and the ON-state resistance becomes further low.
Claims13
A field effect semiconductor device comprising:
- a drift region of a first conductive type of a low impurity density formed on a drain region of the first conductive type of a high impurity density,
- a drain electrode formed on the face of said drain region opposite to a face contacting to said drift region,
- a buried gate region of a second conductive type formed in a central region adjacent to the opposite face to a face contacting to said drain region, in said drift region;
- a buried gate contact region of a second conductive type formed in an end part region adjacent to said opposite face of a face contacting to said drain region, in said drift region;
- a gate contact region of a second conductive type formed on a part of said buried gate contact region;
- a channel region of a first conductive type formed in a region surrounded by said opposite face of said drift region and said gate contact region;
- a source region of a first conductive type formed in a central region adjacent to the surface of said channel region;
- an insulating film formed on a part of the surface of said gate contact region, on the surface of said channel region and on a part of the surface of said source region;
- a gate electrode provided on the surface of said insulating film and the surface of the gate contact region;
- and
- a source electrode provided on said source region.
8 more elements
A field effect semiconductor device comprising:
- a drift region of a first conductive type of a low impurity density formed on a region of a high impurity density;
- a channel region of a first conductive type formed in a range broader than a buried gate region on said buried gate region;
- a source region of a first conductive type formed in a central region adjacent to the surface of said channel region;
- an insulating film formed on the surface of said drift region, on the side surfaces and on the surface of said channel region and on the surface of said source region;
- a buried gate contact region of a second conductive type formed in an end region adjacent to said opposite face to the face contacting with said region of the high impurity density in said drift region;
- a gate electrode formed on said insulating film and said buried gate contact region;
- and
- a source electrode formed on said source region.
5 more elements
A field effect semiconductor device comprising:
- a drift region of a first conductive type of a low impurity density formed on an anode region of a second conductive type of a high impurity density;
- an anode electrode formed on the face of said anode region opposite to the face contacting with said drift region;
- a buried gate region of a second conductive type formed in a central region adjacent to the opposite face to the face contacting with said anode region in said drift region;
- a buried gate contact region of a second conductive type formed in an end region adjacent to said opposite face of the face contacting with said drain region in said drift region;
- a
- gate contact region of a second conductive type formed on a part of said buried gate contact region;
- a channel region of a first conductive type formed in a region surrounded by said opposite face of said drift region and said gate contact region;
- a cathode region of a first conductive type formed in a central region adjacent to the surface of said channel region;
- an insulating film formed on a part of the surface of said gate contact region, the surface of said channel region and the surface of said cathode region;
- a gate electrode provided on the surface of said insulating film and the surface of said gate contact region;
- and
- a cathode electrode provided on said cathode region.
9 more elements
A field effect semiconductor device comprising:
- a drift region of a second conductive type of a low impurity density formed on a cathode region of a first conductive type of a high impurity density;
- a cathode electrode formed on the face of said cathode region opposite to the face contacting with said drift region;
- a buried gate region of a first conductive type formed in a central region adjacent to the opposite face to the face contacting with said cathode region in said drift region;
- a buried gate contact region of a first conductive type formed in an end region adjacent to said opposite face to the face contacting with said cathode region in said drift region;
- a gate contact region of a first conductive type formed on a part of said-buried gate contact region;
- a channel region of a second conductive type formed in a region surrounded by said opposite face of said drift region and said gate contact region;
- an anode region of a second conductive type formed in a central region adjacent to the surface of said channel region;
- an insulating film formed on a part of the surface of said gate contact region, the surface of said channel region and the surface of said anode region;
- a gate electrode provided on the surface of said insulating film and the surface of said gate contact region;
- and
- an anode electrode provided on said anode region.
8 more elements
A fabrication method of a field effect semiconductor device comprising:
- the step of forming a drift region of a first conductive type of a low impurity density on a silicon carbide substrate of the first conductive type of a high impurity density;
- the step of forming a drain electrode on the face of said drain region opposite to the face contacting with said drift region;
- the step of forming a buried gate region of a second conductive type in a central region adjacent to the opposite face to the face contacting with said drain region within said drift region;
- the step of forming-a buried gate contact region of a second conductive type in an end region adjacent to said opposite face to the face contacting with said drain region within said drift region;
- the step of forming a gate contact region of a second conductive type on a part of said buried gate contact region;
- the step of forming a channel region of a first conductive type in a region surrounded by said opposite face of said drift region and said gate contact region;
- the step of forming a source region of a first conductive type in a central region adjacent to the surface of said channel region;
- the step of forming an insulating film on a-part of the surface of said gate contact region, the surface of said channel region and the surface of said source region;
- the step of forming a, gate electrode on the surface of said insulating film and the surface of the gate contact region;
- and
- the step of forming a source electrode on said source region.
8 more elements
A fabrication method of a field effect semiconductor device comprising:
- the step of forming a drift region of a first conductive type of a low impurity density on a silicon carbide substrate serving as an anode region of a second conductive type of a high impurity density;
- the step of forming an anode electrode on the face of said anode region opposite to the face contacting with said drift region;
- the step of forming a buried gate region of a second conductive type in a central region adjacent to the opposite face to the face contacting with said anode region within said drift region;
- the step of forming a buried gate contact region of a second conductive type in an end region adjacent to said opposite face to the face contacting with said drain, region within said drift region;
- the step of forming a gate contact region of a second conductive type on a part of said buried gate contact region;
- the step of forming a channel region of a first conductive type in a region surrounded by said opposite face of said drift region and said gate contact region;
- the step of forming a cathode region of a first conductive type in a central region adjacent to the surface of said channel region;
- the step of forming an insulating film on a part of the surface of said gate contact region, the surface of said channel region and the surface of said cathode region;
- the step of forming a gate electrode on the surface of said insulating film and the surface of said gate contact region;
- and
- the step of forming a cathode electrode on said cathode region.
8 more elements
A fabrication method of a field effect semiconductor device comprising:
- the step of forming a drift region of a second conductive type of a low impurity density on a silicon carbide substrate of a first conductive type of a high impurity density;
- the step of forming a cathode electrode on the surface of said cathode region opposite to the face contacting with said drift region;
- the step of forming a buried gate region of a first conductive type in a central region adjacent to the opposite face to the face contacting with said cathode region within said drift region;
- the step of forming a buried gate contact region of a first conductive type in an end region adjacent to said opposite face to the face contacting with said cathode region within said drift region;
- the step of forming a gate contact region of a first conductive type on a part of said buried gate contact region;
- the step of forming a channel region of a second conductive type in a region surrounded by said opposite face of said drift region and said gate contact region;
- the step of forming an anode region of a second conductive type in a central region adjacent to the surface of said channel region;
- the step of forming an insulating film on a part of the surface of said gate contact region, the surface of said channel region and the surface of said anode region;
- the step of forming a gate electrode on the surface of said insulating film and the surface of said gate contact region;
- and
- the step of forming an anode electrode on said anode region.
8 more elements
Dependencies are inferred from the claim text.