SEMICONDUCTOR DEVICE
First Claim
1. A method for producing a semiconductor device, comprising:
- forming a structure in which a trench gate structure is provided in a front surface side of semiconductor layers in which on a main surface of a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type that has a lower impurity concentration than that of the first semiconductor layer, a third semiconductor layer of a second conductivity type, and a fourth semiconductor layer of the first conductivity type are sequentially provided;
forming a contact groove passing through the fourth semiconductor layer in the contiguous trench gate structures and reaching the third semiconductor layer; and
forming a fifth semiconductor layer by introducing an impurity of the second conductive type into the second semiconductor layer by a plurality of times sequentially from a first introduction position in the second semiconductor layer not reaching the main surface of the first semiconductor layer to a shallower position therein in the third semiconductor layer side so that the fourth semiconductor layer in which the contact grooves are selectively formed serves as a mask,the fifth semiconductor layer being thinner from an uppermost portion to a lowermost portion, anda dose amount in impurity introduction into the first introduction position being higher than a dose amount of impurity introduction into the shallower position than the first introduction position.
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Accused Products
Abstract
A semiconductor device includes: a first semiconductor layer of a first conductivity type; a second semiconductor layer of the first conductivity type provided on a main surface of the first semiconductor layer and having a lower impurity concentration than that of the first semiconductor layer; a third semiconductor layer of a second conductivity type provided on the second semiconductor layer; a fourth semiconductor layer of the first conductivity type selectively provided on the third semiconductor layer; a gate electrode provided in a trench passing through the third semiconductor layer and reaching the second semiconductor layer; a first main electrode contacting the fourth semiconductor layer and contacting the third semiconductor layer through a contact groove provided to pass through the fourth semiconductor layer between the contiguous gate electrodes; a second main electrode provided on an opposite surface to the main surface of the first semiconductor layer; and a fifth semiconductor layer of the second conductivity type provided in an interior portion of the second semiconductor layer corresponding to a part under the contact groove. An uppermost portion of the fifth semiconductor layer contacts the third semiconductor layer, a lowermost portion of the fifth semiconductor layer has a higher impurity concentration than that of the other portion in the fifth semiconductor layer and is located in the second semiconductor layer and not contacting the first semiconductor layer, and the fifth semiconductor layer is narrower from the uppermost portion to the lower most portion.
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Citations
10 Claims
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1. A method for producing a semiconductor device, comprising:
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forming a structure in which a trench gate structure is provided in a front surface side of semiconductor layers in which on a main surface of a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type that has a lower impurity concentration than that of the first semiconductor layer, a third semiconductor layer of a second conductivity type, and a fourth semiconductor layer of the first conductivity type are sequentially provided; forming a contact groove passing through the fourth semiconductor layer in the contiguous trench gate structures and reaching the third semiconductor layer; and forming a fifth semiconductor layer by introducing an impurity of the second conductive type into the second semiconductor layer by a plurality of times sequentially from a first introduction position in the second semiconductor layer not reaching the main surface of the first semiconductor layer to a shallower position therein in the third semiconductor layer side so that the fourth semiconductor layer in which the contact grooves are selectively formed serves as a mask, the fifth semiconductor layer being thinner from an uppermost portion to a lowermost portion, and a dose amount in impurity introduction into the first introduction position being higher than a dose amount of impurity introduction into the shallower position than the first introduction position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification