Semiconductor device
First Claim
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1. A semiconductor device, comprising:
- a semiconductor layer made of SiC;
a source region of a first conductivity type formed in the semiconductor layer, the source region forming a surface of the semiconductor layer;
a body region of a second conductivity type formed in the semiconductor layer, the body region being in contact with the source region from a side of a back surface of the semiconductor layer;
a drain region of a first conductivity type formed in the semiconductor layer, the drain region being in contact with the body region from the side of the back surface of the semiconductor layer;
a gate trench dug down in the semiconductor layer from the surface thereof, the gate trench passing through the source region and the body region and the deepest portion thereof reaching to reach the drain region;
a gate insulating film formed on an inner surface of the gate trench;
a gate electrode embedded in the gate trench on the gate insulating film;
a source trench dug down in the semiconductor layer from the surface thereof, the source trench passing through the source region and the body region, and the deepest portion thereof reaching to reach a first conductivity type part of the drain region; and
a conductive material embedded in the source trench, the conductive material having a first layer conforming to a side surface and a bottom surface of the source trench and a second layer formed on the first layer;
wherein the body region includes a first portion exposed from a side surface of the gate trench and a second portion exposed from the side surface of the source trench,wherein a high-concentration impurity region is formed in the second portion of the body region and is in contact with the drain region, wherein the second layer includes at least a lower layer conforming to the first layer to define a space inside the source trench, and an upper layer embedded in the space,wherein an ohmic contact is selectively formed between the first layer and a high-concentration impurity region of the body region in an ohmic contact area,wherein a non-ohmic contact is selectively formed between the first layer and the drain region in a non-ohmic contact area, andwherein the ohmic contact area and the non-ohmic contact area are adjacent.
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Abstract
The semiconductor device according to the present invention includes: a semiconductor layer made of SiC; an impurity region formed by doping the semiconductor layer with an impurity; and a contact wire formed on the semiconductor layer in contact with the impurity region, while the contact wire has a polysilicon layer in the portion in contact with the impurity region, and has a metal layer on the polysilicon layer.
93 Citations
25 Claims
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1. A semiconductor device, comprising:
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a semiconductor layer made of SiC; a source region of a first conductivity type formed in the semiconductor layer, the source region forming a surface of the semiconductor layer; a body region of a second conductivity type formed in the semiconductor layer, the body region being in contact with the source region from a side of a back surface of the semiconductor layer; a drain region of a first conductivity type formed in the semiconductor layer, the drain region being in contact with the body region from the side of the back surface of the semiconductor layer; a gate trench dug down in the semiconductor layer from the surface thereof, the gate trench passing through the source region and the body region and the deepest portion thereof reaching to reach the drain region; a gate insulating film formed on an inner surface of the gate trench; a gate electrode embedded in the gate trench on the gate insulating film; a source trench dug down in the semiconductor layer from the surface thereof, the source trench passing through the source region and the body region, and the deepest portion thereof reaching to reach a first conductivity type part of the drain region; and a conductive material embedded in the source trench, the conductive material having a first layer conforming to a side surface and a bottom surface of the source trench and a second layer formed on the first layer; wherein the body region includes a first portion exposed from a side surface of the gate trench and a second portion exposed from the side surface of the source trench, wherein a high-concentration impurity region is formed in the second portion of the body region and is in contact with the drain region, wherein the second layer includes at least a lower layer conforming to the first layer to define a space inside the source trench, and an upper layer embedded in the space, wherein an ohmic contact is selectively formed between the first layer and a high-concentration impurity region of the body region in an ohmic contact area, wherein a non-ohmic contact is selectively formed between the first layer and the drain region in a non-ohmic contact area, and wherein the ohmic contact area and the non-ohmic contact area are adjacent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 24)
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16. A semiconductor device, comprising:
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a semiconductor layer made of SiC; a source region formed in the semiconductor layer, the source region forming a surface of the semiconductor layer; a body region formed in the semiconductor layer, the body region being in contact with the source region from a side of a back surface of the semiconductor layer; a drain region formed in the semiconductor layer, the drain region being in contact with the body region from the side of the back surface of the semiconductor layer; a gate trench dug down in the semiconductor layer from the surface thereof, the gate trench passing through the source region and the body region and the deepest portion thereof to reach the drain region; a gate insulating film formed on an inner surface of the gate trench; a gate electrode embedded in the gate trench on the gate insulating film; a source trench dug down in the semiconductor layer from the surface thereof, the source trench passing through the source region and the body region to reach the drain region; and a conductive material embedded in the source trench, the conductive material having a first layer conforming to a side surface and a bottom surface of the source trench and a second layer formed on the first layer; wherein the body region includes a first portion exposed from a side surface of the gate trench and a second portion exposed from the side surface of the source trench, wherein a high-concentration impurity region is formed in the second portion of the body region and is in contact with the drain region, wherein the first layer selectively forms an ohmic contact and a first junction with respect to the semiconductor layer, the first junction having a smaller junction barrier than the diffusion potential of a body diode intrinsic in the semiconductor device which is a PN diode formed by junction between the body region and the drain region, and wherein the second layer includes at least a lower layer conforming to the first layer to define a space inside the source trench, and an upper layer embedded in the space, wherein the ohmic contact is selectively formed between the first layer and the high-concentration impurity region of the body region in an ohmic contact area, wherein a non-ohmic contact is selectively formed between the first layer and the drain region in a non-ohmic contact area, and wherein the ohmic contact area and the non-ohmic contact area are adjacent. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 25)
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Specification
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Current AssigneeROHM Co., Ltd.
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Original AssigneeROHM Co., Ltd.
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InventorsNakano, Yuki
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Primary Examiner(s)Nguyen, Tuan H.
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Application NumberUS15/933,357Time in Patent Office831 DaysField of Search257 77, 257330, 257382, 438326, 438330US Class CurrentCPC Class CodesN/A
