SEMICONDUCTOR DEVICE HAVING FIELD PLATE ELECTRODE AND METHOD FOR MANUFACTURING THE SAME
First Claim
1. A semiconductor device, comprising:
- a first semiconductor layer of a first conductivity type having a first impurity concentration;
a second semiconductor layer of the first conductivity type formed on the first semiconductor layer and having a second impurity concentration lower than the first impurity concentration;
a field plate electrode formed in a lower portion of a trench formed in the second semiconductor layer on a bottom surface side of the trench through a first insulating film so as to bury the lower portion of the trench;
a second insulating film formed in the upper portion of the trench so as to be in contact with the top surface of the field plate electrode;
a gate electrode formed in the upper portion of the trench on an opening side of the trench through a gate insulating film so as to bury the upper portion of the trench to sandwich the second insulating film;
,a base layer of a second conductivity type formed in the upper portion of the second semiconductor layer and having a third impurity concentration; and
a source layer of the first conductivity type formed in the upper portion of the base layer and having a fourth impurity concentration higher than the second impurity concentration.
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Accused Products
Abstract
According to one embodiment, in a semiconductor device, a first semiconductor layer of a first conductivity type has a first impurity concentration. A second semiconductor layer of the first conductivity type is formed on the first semiconductor layer and has a second impurity concentration lower than the first impurity concentration. A field plate electrode is formed in a lower portion of a trench formed in the second semiconductor layer through a first insulating film so as to bury the lower portion of the trench. A second insulating film is formed in the upper portion of the trench so as to be in contact with the top surface of the field plate electrode. A gate electrode is formed in the upper portion of the trench through a gate insulating film so as to bury the upper portion of the trench to sandwich the second insulating film.
20 Citations
18 Claims
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1. A semiconductor device, comprising:
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a first semiconductor layer of a first conductivity type having a first impurity concentration; a second semiconductor layer of the first conductivity type formed on the first semiconductor layer and having a second impurity concentration lower than the first impurity concentration; a field plate electrode formed in a lower portion of a trench formed in the second semiconductor layer on a bottom surface side of the trench through a first insulating film so as to bury the lower portion of the trench; a second insulating film formed in the upper portion of the trench so as to be in contact with the top surface of the field plate electrode; a gate electrode formed in the upper portion of the trench on an opening side of the trench through a gate insulating film so as to bury the upper portion of the trench to sandwich the second insulating film;
,a base layer of a second conductivity type formed in the upper portion of the second semiconductor layer and having a third impurity concentration; and a source layer of the first conductivity type formed in the upper portion of the base layer and having a fourth impurity concentration higher than the second impurity concentration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for manufacturing a semiconductor device, comprising:
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forming a second semiconductor layer of a first conductivity type having a second impurity concentration on a first semiconductor layer of the first conductivity type having a first impurity concentration, the second impurity concentration being lower than the first impurity concentration; forming a trench in the second semiconductor layer; forming a first conductive film in the trench through a first insulating film so as to bury the trench; removing the first insulating film of the upper portion of the trench on an opening side of the trench so as to expose the upper portion of the trench and the upper portion of the first conductive film; oxidizing the side surface of the upper portion of the exposed trench and the upper portion of the exposed first conductive film so as to form a gate insulating film on the side surface of the upper portion of the trench and modify the entire upper portion of the first conductive film into a second insulating film; forming a gate electrode in the upper portion of the trench through the gate insulating film so as to bury the upper portion of the trench to sandwich the second insulating film; forming a base layer having a third impurity concentration on the upper portion of the second semiconductor layer; and forming a source layer of the first conductivity type having a fourth impurity concentration higher than the second impurity concentration on the upper portion of the base layer. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification