Method for fabricating a trench MOS power transistor
First Claim
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1. A method for fabricating a trench MOS power transistor, the method which comprises:
- forming a trench in a semiconductor body;
coating walls and a bottom of the trench with a first insulating film of a given final thickness by applying the first insulating film as a plurality of thermally oxidized and deposited layers;
filling a lower end of the trench with an auxiliary layer;
removing the first insulating film in regions not coated with the auxiliary layer;
removing the auxiliary layer;
growing a second insulating film on uncovered walls at an upper end of the trench such that the second insulating film is thinner than the given final thickness of the first insulating film;
filling the trench at least partly with a conductive material such that the conductive material is insulated from an inner surface of the trench by the first insulating layer and the second insulating layer; and
introducing source zones and body zones into the semiconductor body and providing metallization layers for providing contacting connections.
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Abstract
A method for fabricating a trench MOS transistor includes the step of at least partly filling the trench with a conductive material which is isolated from the inner surface of the trench by an insulating layer. The insulating layer has a layer thickness that is larger in the region of the lower end of the trench than at the upper end of the trench.
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Citations
15 Claims
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1. A method for fabricating a trench MOS power transistor, the method which comprises:
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forming a trench in a semiconductor body;
coating walls and a bottom of the trench with a first insulating film of a given final thickness by applying the first insulating film as a plurality of thermally oxidized and deposited layers;
filling a lower end of the trench with an auxiliary layer;
removing the first insulating film in regions not coated with the auxiliary layer;
removing the auxiliary layer;
growing a second insulating film on uncovered walls at an upper end of the trench such that the second insulating film is thinner than the given final thickness of the first insulating film;
filling the trench at least partly with a conductive material such that the conductive material is insulated from an inner surface of the trench by the first insulating layer and the second insulating layer; and
introducing source zones and body zones into the semiconductor body and providing metallization layers for providing contacting connections. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification