Semiconductor device and method of fabricating same
First Claim
1. A semiconductor device comprising:
- a first semiconductor layer of a first conductivity type having first and second major surfaces;
a second semiconductor layer of a second conductivity type formed on said first major surface;
a third semiconductor layer of the first conductivity type selectively formed on said second semiconductor layer;
a groove extending from a top surface of said third semiconductor layer through said second semiconductor layer into said first semiconductor layer;
a dielectric layer formed at least on an inner wall of said groove which is in face-to-face relation to said second semiconductor layer;
a control electrode formed on said inner wall of said groove through said dielectric layer; and
an insulating layer formed on a part of an inner wall of said groove which is in face-to-face relation to said third semiconductor layer and containing an impurity of the first conductivity type,a portion of said third semiconductor layer adjacent to said groove having a uniform impurity concentration in the vertical direction along said groove.
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Accused Products
Abstract
There is disclosed a semiconductor device having a vertical channel MOS gate structure wherein grooves (40) are formed from the top surface of source regions (5) through a body (3) into an N diffusion region (2) and wherein buried gate electrodes (4) fill an inner part of said grooves (40) which is in face-to-face relation to the N diffusion region (2) across gate oxide films (13) while buried oxide films (15) including diffusion source impurities fill an inner part thereof which is in face-to-face relation to the source regions (5). The impurity concentration of the source regions (5) is distributed uniformly in the vertical direction of the grooves (40) and decreases lateraly away from the grooves (40). A current flows through the source region along the grooves and a resistance thereagainst is held small in an ON-state. The grooves may be formed with narrow spacing. The size reduction and high integration of the semiconductor device are achieved as well as reduction in ON-resistance.
75 Citations
21 Claims
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1. A semiconductor device comprising:
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a first semiconductor layer of a first conductivity type having first and second major surfaces; a second semiconductor layer of a second conductivity type formed on said first major surface; a third semiconductor layer of the first conductivity type selectively formed on said second semiconductor layer; a groove extending from a top surface of said third semiconductor layer through said second semiconductor layer into said first semiconductor layer; a dielectric layer formed at least on an inner wall of said groove which is in face-to-face relation to said second semiconductor layer; a control electrode formed on said inner wall of said groove through said dielectric layer; and an insulating layer formed on a part of an inner wall of said groove which is in face-to-face relation to said third semiconductor layer and containing an impurity of the first conductivity type, a portion of said third semiconductor layer adjacent to said groove having a uniform impurity concentration in the vertical direction along said groove. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of fabricating a semiconductor device, comprising the steps of:
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(a) providing a first semiconductor layer of a first conductivity type having first and second major surfaces; (b) forming a second semiconductor layer of a second conductivity type on said first major surface; (c) forming a groove extending through from a top surface of said second semiconductor layer into said first semiconductor layer, said groove having a first region in the vicinity of said top surface of said second semiconductor layer and a second region other than said first region; (d) forming a dielectric layer on an inner wall of said groove in said second region; (e) forming a control electrode on said dielectric layer; (f) forming an insulating layer containing a diffusion source impurity of the first conductivity type at least on an inner wall of said groove in said first region; and (g) diffusing said diffusion source impurity from said insulating layer to selectively form a third semiconductor layer of the first conductivity type in contact with said groove on said second semiconductor layer, said third semiconductor layer being at least longer than said first region in the direction of the thickness of said second semiconductor layer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification