Semiconductor device having trench gate structure and manufacturing method thereof
First Claim
1. A method of manufacturing a semiconductor device comprising:
- forming a second semiconductor layer of a second conductivity type on a first semiconductor layer of a first conductivity type;
forming a trench which extends from the surface of the second semiconductor layer, penetrates the second semiconductor layer and has depth to reach at least a portion lying near the first semiconductor layer;
forming an insulating film on side walls and a bottom portion of the trench;
forming a third semiconductor layer of the first conductivity type in the first semiconductor layer near the bottom of the trench, the third semiconductor layer having an impurity concentration higher than that of the first semiconductor layer;
forming a fourth semiconductor layer of the second conductivity type by ion-implantating using the third semiconductor layer as a stopper in a region deeper than the second semiconductor layer; and
forming a gate electrode at least partly on the insulating film in the trench.
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Accused Products
Abstract
A vertical MOSFET includes a base region formed on a drain region and a source region formed in the base region. A trench is formed to extend from the surface of the source region and penetrate the source region and has depth to reach a portion near the drain region. A gate insulating film is formed on the side walls and bottom portion of the trench and the gate electrode is formed in the trench. The impurity concentration profile of the base region has a first peak in a portion near the interface between the source region and the base region and a second peak which is formed in a portion near the interface between the base region and the drain region and is lower than the first peak. The threshold voltage is determined based on the first peak and the dose amount is determined based on the second peak.
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Citations
19 Claims
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1. A method of manufacturing a semiconductor device comprising:
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forming a second semiconductor layer of a second conductivity type on a first semiconductor layer of a first conductivity type;
forming a trench which extends from the surface of the second semiconductor layer, penetrates the second semiconductor layer and has depth to reach at least a portion lying near the first semiconductor layer;
forming an insulating film on side walls and a bottom portion of the trench;
forming a third semiconductor layer of the first conductivity type in the first semiconductor layer near the bottom of the trench, the third semiconductor layer having an impurity concentration higher than that of the first semiconductor layer;
forming a fourth semiconductor layer of the second conductivity type by ion-implantating using the third semiconductor layer as a stopper in a region deeper than the second semiconductor layer; and
forming a gate electrode at least partly on the insulating film in the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of manufacturing a semiconductor device comprising:
- forming a first semiconductor layer of a first conductivity type;
forming a first part of a base layer of a second conductivity type in the first semiconductor layer;
forming a trench in the first and the second semiconductor layers;
forming an insulating film on side walls and a bottom portion of the trench;
forming a second semiconductor layer of the first conductivity type in the first semiconductor layer near the bottom of the trench, the second semiconductor layer having an impurity concentration higher than that of the first semiconductor layer;
forming a second part of the base layer of the second conductivity type in the first semiconductor layer using the second semiconductor layer as a stopper in a region deeper than the first part of the base layer; and
forming a gate electrode at least partly on the insulating film in the trench, wherein the base layer is formed by performing ion-implantation a plurality of times before and after forming the second semiconductor layer. - View Dependent Claims (15, 16, 17, 18, 19)
- forming a first semiconductor layer of a first conductivity type;
Specification