Semiconductor device
First Claim
1. A semiconductor device comprising:
- a semiconductor substrate of a first conductivity type;
a drift layer of the first conductivity type formed on a surface of said semiconductor substrate;
a plurality of first well regions of a second conductivity type formed selectively in a surface region of said drift layer;
a source region of the first conductivity type formed selectively in a surface region of each of said first well regions;
a gate electrode formed over said first well regions and said drift layer thereacross through an insulating film;
a second well region of the second conductivity type in said drift layer below said gate electrode, and connected to each of said first well regions adjacent to one another;
a source electrode connected to said source region; and
a drain electrode formed on a rear surface of said semiconductor substrate,wherein a second conductivity type impurity concentration profile of said second well region in a depth direction includes a point which is deeper than said surface region of said drift layer and where a second conductivity type impurity concentration at said point is higher than a second conductivity type impurity concentration at said surface region of said drift layer.
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Accused Products
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
19 Claims
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1. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type formed on a surface of said semiconductor substrate; a plurality of first well regions of a second conductivity type formed selectively in a surface region of said drift layer; a source region of the first conductivity type formed selectively in a surface region of each of said first well regions; a gate electrode formed over said first well regions and said drift layer thereacross through an insulating film; a second well region of the second conductivity type in said drift layer below said gate electrode, and connected to each of said first well regions adjacent to one another; a source electrode connected to said source region; and a drain electrode formed on a rear surface of said semiconductor substrate, wherein a second conductivity type impurity concentration profile of said second well region in a depth direction includes a point which is deeper than said surface region of said drift layer and where a second conductivity type impurity concentration at said point is higher than a second conductivity type impurity concentration at said surface region of said drift layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A semiconductor device comprising:
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a semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type formed on a surface of said semiconductor substrate; a plurality of first well regions of a second conductivity type formed selectively in a surface region of said drift layer; a source region of the first conductivity type formed selectively in a surface region of each of said first well regions; a JFET region which is in a gap region between said first well regions adjacent to one another; a gate electrode formed over said first well regions and said JFET region thereacross through an insulating film; a second well region of the second conductivity type in said JFET region, and connected to each of said first well regions adjacent to one another; a layer formed between said insulating film and said second well region, and in which a second conductivity type impurity concentration is lower than a second conductivity type impurity concentration in said second well region; a source electrode connected to said source region; and a drain electrode formed on a rear surface of said semiconductor substrate. - View Dependent Claims (19)
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Specification