Insulated trench semiconductor device with particular layer structure
First Claim
1. An insulated gate semiconductor device, comprising:
- a first semiconductor layer of a first conductivity type having first and second main surfacesa second semiconductor layer of a second conductivity type provided over the first main surface of said first semiconductor layer;
a third semiconductor layer of the second conductivity type provided in close contact on a surface of said second semiconductor layer and having an impurity concentration higher than the impurity concentration of said second semiconductor layer;
a fourth semiconductor layer of the first conductivity type provided in close contact on a surface of said third semiconductor layer;
a fifth semiconductor layer of the second conductivity type selectively provided in a surface of said fourth semiconductor layer;
a trench having an opening in a surface of said fifth semiconductor layer and having a depth extending through at least said fourth semiconductor layer from the surface of said fifth semiconductor layer;
an insulating film provided on an inner entire wall of said trench;
a control electrode provided in said trench to face said fourth semiconductor layer through said insulating film;
a first main electrode provided on the surface of said fourth and fifth semiconductor layers; and
a second main electrode provided on the second main surface of said first semiconductor layer, wherein said second semiconductor layer is thicker than said third semiconductor layer.
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Accused Products
Abstract
It is an object to compatibly realize a decrease in an on-state voltage and an increase in a current capable of turn-off. An N layer (43) having an impurity concentration higher than that of an N- layer (42) is formed between the N- layer (42) and a P base layer (44). In the exposed surface of the P base layer (44) connected to an emitter electrode (51), a P+ layer (91) having an impurity concentration higher than that of the P base layer (44) is formed. The formation of the N layer (43) allows the carrier distribution in the N- layer (42) to be close to the carrier distribution of a diode, so that the on-state voltage is decreased while maintaining high the current value capable of turn-off. Furthermore, the P+ layer (91) allows holes to easily go through form the P base layer (44) to the emitter electrode (51), which increases the current value capable of turn-off.
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Citations
15 Claims
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1. An insulated gate semiconductor device, comprising:
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a first semiconductor layer of a first conductivity type having first and second main surfaces a second semiconductor layer of a second conductivity type provided over the first main surface of said first semiconductor layer; a third semiconductor layer of the second conductivity type provided in close contact on a surface of said second semiconductor layer and having an impurity concentration higher than the impurity concentration of said second semiconductor layer; a fourth semiconductor layer of the first conductivity type provided in close contact on a surface of said third semiconductor layer; a fifth semiconductor layer of the second conductivity type selectively provided in a surface of said fourth semiconductor layer; a trench having an opening in a surface of said fifth semiconductor layer and having a depth extending through at least said fourth semiconductor layer from the surface of said fifth semiconductor layer; an insulating film provided on an inner entire wall of said trench; a control electrode provided in said trench to face said fourth semiconductor layer through said insulating film; a first main electrode provided on the surface of said fourth and fifth semiconductor layers; and a second main electrode provided on the second main surface of said first semiconductor layer, wherein said second semiconductor layer is thicker than said third semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An insulated gate semiconductor device, comprising:
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a first semiconductor layer of a first conductivity type having first and second main surfaces; a second semiconductor layer of a second conductivity type provided over the first main surface of said first semiconductor layer; a third semiconductor layer of the second conductivity type provided in close contact on a surface of said second semiconductor layer and having an impurity concentration higher than the impurity concentration of said second semiconductor layer; a fourth semiconductor layer of the first conductivity type provided in close contact on a surface of said third semiconductor layer; a fifth semiconductor layer of the second conductivity type selectively provided in a surface of said fourth semiconductor layer; a trench having an opening in a surface of said fifth semiconductor layer and having a trench depth extending through said fourth semiconductor layer and into said third semiconductor layer from the surface of said fifth semiconductor layer; an insulating film provided on an inner wall of said trench; a control electrode provided in said trench to face said fourth semiconductor layer through said insulating film; a first main electrode provided on the surface of said fourth and fifth semiconductor layers; a second main electrode provided on the second main surface of said first semiconductor layer; and wherein a depth of a boundary between said third semiconductor layer and said second semiconductor layer does not exceed a critical value at which a rapid decrease appears in a breakdown voltage of said insulated gate semiconductor device with an increase in said boundary depth.
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14. An insulated gate semiconductor device, comprising:
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a first semiconductor layer of a first conductivity type having first and second main surfaces; a second semiconductor layer of a second conductivity type provided over the first main surface of said first semiconductor layer; a third semiconductor layer of the second conductivity type provided in close contact on a surface of said second semiconductor layer and having an impurity concentration higher than the impurity concentration of said second semiconductor layer; a fourth semiconductor layer of the first conductivity type provided in close contact on a surface of said third semiconductor layer; a fifth semiconductor layer of the second conductivity type selectively provided in a surface of said fourth semiconductor layer; a trench having an opening in a surface of said fifth semiconductor layer and having a trench depth extending through said fourth semiconductor layer into said third semiconductor layer from the surface of said fifth semiconductor layer; an insulating film provided on an inner wall of said trench; a control electrode provided in said trench to face said fourth semiconductor layer through said insulating film; a first main electrode provided on the surface of said fourth and fifth semiconductor layers; a second main electrode provided on the second main surface of said first semiconductor layer; an eighth semiconductor layer of the first conductivity type formed to surround a bottom of said trench and having an impurity concentration higher than that in said second semiconductor layer; and wherein said eighth semiconductor layer is surrounded by said third semiconductor layer. - View Dependent Claims (15)
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Specification