Semiconductor device
First Claim
1. A semiconductor device comprising:
- a semiconductor substrate of a first conductivity type;
a semiconductor layer on a surface of said semiconductor substrate;
a source electrode on a surface of said semiconductor layer;
a drain electrode on a rear surface of said semiconductor substrate; and
a gate electrode forming a channel region in said semiconductor layer;
wherein said semiconductor layer comprises;
a first conductivity region on said surface of said semiconductor substrate;
a plurality of first well regions of a second conductivity type on said first conductivity region, facing said gate electrode with an insulating film therebetween;
a source region of the first conductivity type in a surface region of each of said first well regions, connected to said source electrode; and
a second well region of the second conductivity type in said semiconductor layer which is vertically overlapped by the gate electrode, the second well region of the second conductivity type in said semiconductor layer overlapping the drain electrode,wherein a second conductivity type impurity concentration profile of said second well region includes a maximum value point, which is at a position which is not vertically overlapped by the first well region, which is deeper than a surface of said second well region between said gate electrode and said drain electrode, andwherein a second conductivity type impurity concentration of the maximum value point is at least ten times greater than a second conductivity type impurity concentration of the surface of said second well region.
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Abstract
A semiconductor device having a low feedback capacitance and a low switching loss. The semiconductor device includes: a substrate; a drift layer formed on a surface of the semiconductor substrate; a plurality of first well regions formed on a surface of the drift layer; a source region which is an area formed on a surface of each of the first well regions and defining, as a channel region, the surface of each of the first well regions interposed between the area and the drift layer; a gate electrode formed over the channel region and the drift layer thereacross through a gate insulating film; and second well regions buried inside the drift layer below the gate electrode and formed to be individually connected to each of the first well regions adjacent to one another.
26 Citations
24 Claims
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1. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type; a semiconductor layer on a surface of said semiconductor substrate; a source electrode on a surface of said semiconductor layer; a drain electrode on a rear surface of said semiconductor substrate; and a gate electrode forming a channel region in said semiconductor layer; wherein said semiconductor layer comprises; a first conductivity region on said surface of said semiconductor substrate; a plurality of first well regions of a second conductivity type on said first conductivity region, facing said gate electrode with an insulating film therebetween; a source region of the first conductivity type in a surface region of each of said first well regions, connected to said source electrode; and a second well region of the second conductivity type in said semiconductor layer which is vertically overlapped by the gate electrode, the second well region of the second conductivity type in said semiconductor layer overlapping the drain electrode, wherein a second conductivity type impurity concentration profile of said second well region includes a maximum value point, which is at a position which is not vertically overlapped by the first well region, which is deeper than a surface of said second well region between said gate electrode and said drain electrode, and wherein a second conductivity type impurity concentration of the maximum value point is at least ten times greater than a second conductivity type impurity concentration of the surface of said second well region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type; a semiconductor layer on a surface of said semiconductor substrate; a source electrode on a surface of said semiconductor layer; a drain electrode on a rear surface of said semiconductor substrate; and a gate electrode forming a channel region in said semiconductor layer; wherein said semiconductor layer comprises; a first conductivity region on said surface of said semiconductor substrate; a plurality of first well regions of a second conductivity type on said first conductivity region, facing said gate electrode with an insulating film therebetween; a source region of the first conductivity type in a surface region of each of said first well regions, connected to said source electrode; and a second well region of the second conductivity type in said semiconductor layer which is vertically overlapped by the gate electrode, the second well region of the second conductivity type in said semiconductor layer overlapping the drain electrode, wherein a second conductivity type impurity concentration profile of said second well region includes a maximum value point, which is at a position which is not vertically overlapped by the first well region, which is deeper than a surface of said second well region between said gate electrode and said drain electrode, and wherein a region of the first conductivity type overlies said second well region.
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Specification