SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A semiconductor device including a first region having a Schottky barrier diode formed therein and a second region having a power MISFET formed therein,the first region comprising:
- (a1) a semiconductor substrate of a first conductivity type having an upper surface and a lower surface on a side opposite to the upper surface;
(a2) a first semiconductor layer of the first conductivity type formed over the upper surface of the semiconductor substrate;
(a3) a second semiconductor layer of the first conductivity type formed over the first semiconductor layer;
(a4) a first metal film formed over the second semiconductor layer, the first metal film and the second semiconductor layer forming a Schottky junction; and
(a5) a second metal film formed over the lower surface of the semiconductor substrate,the second region comprising;
(b1) the semiconductor substrate;
(b2) the first semiconductor layer formed over the semiconductor substrate;
(b3) a channel region formed in the first semiconductor layer and having a second conductivity type opposite to the first conductivity type;
(b4) a trench penetrating through the channel region and reaching the first semiconductor layer;
(b5) a gate insulating film formed over an inner wall of the trench;
(b6) a gate electrode formed over the gate insulating film and filled in the trench;
(b7) a source region of the first conductivity type contiguous to the trench and formed over the channel region;
(b8) the first metal film formed over the source region and electrically coupled to the source region; and
(b9) the second metal film formed over the lower surface of the semiconductor substrate,wherein the first metal film functions as an anode electrode of the Schottky barrier diode in the first region and as a source electrode of the power MISFET in the second region,wherein the second metal film functions as a cathode electrode of the Schottky barrier diode in the first region and as a drain electrode of the power MISFET in the second region,wherein the second semiconductor layer has a doping concentration lower than that of the first semiconductor layer, andwherein a boundary between the first semiconductor layer and the second semiconductor layer is formed in a region as deep as the bottom portion of the trench or in a region shallower than the bottom portion of the trench.
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Accused Products
Abstract
Provided is a technology, in a semiconductor device having a power MISFET and a Schottky barrier diode on one semiconductor substrate, capable of suppressing a drastic increase in the on-resistance of the power MISFET while making the avalanche breakdown voltage of the Schottky barrier diode greater than that of the power MISFET. In the present invention, two epitaxial layers, one having a high doping concentration and the other having a low doping concentration, are formed over a semiconductor substrate and the boundary between these two epitaxial layers is located in a region equal in depth to or shallower than the bottom portion of a trench.
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Citations
25 Claims
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1. A semiconductor device including a first region having a Schottky barrier diode formed therein and a second region having a power MISFET formed therein,
the first region comprising: -
(a1) a semiconductor substrate of a first conductivity type having an upper surface and a lower surface on a side opposite to the upper surface; (a2) a first semiconductor layer of the first conductivity type formed over the upper surface of the semiconductor substrate; (a3) a second semiconductor layer of the first conductivity type formed over the first semiconductor layer; (a4) a first metal film formed over the second semiconductor layer, the first metal film and the second semiconductor layer forming a Schottky junction; and (a5) a second metal film formed over the lower surface of the semiconductor substrate, the second region comprising; (b1) the semiconductor substrate; (b2) the first semiconductor layer formed over the semiconductor substrate; (b3) a channel region formed in the first semiconductor layer and having a second conductivity type opposite to the first conductivity type; (b4) a trench penetrating through the channel region and reaching the first semiconductor layer; (b5) a gate insulating film formed over an inner wall of the trench; (b6) a gate electrode formed over the gate insulating film and filled in the trench; (b7) a source region of the first conductivity type contiguous to the trench and formed over the channel region; (b8) the first metal film formed over the source region and electrically coupled to the source region; and (b9) the second metal film formed over the lower surface of the semiconductor substrate, wherein the first metal film functions as an anode electrode of the Schottky barrier diode in the first region and as a source electrode of the power MISFET in the second region, wherein the second metal film functions as a cathode electrode of the Schottky barrier diode in the first region and as a drain electrode of the power MISFET in the second region, wherein the second semiconductor layer has a doping concentration lower than that of the first semiconductor layer, and wherein a boundary between the first semiconductor layer and the second semiconductor layer is formed in a region as deep as the bottom portion of the trench or in a region shallower than the bottom portion of the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A manufacturing method of a semiconductor device, comprising the steps of:
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(a) preparing a multilayer substrate having a semiconductor substrate of a first conductivity type, a first semiconductor layer of the first conductivity type formed over the semiconductor substrate, and a second semiconductor layer of the first conductivity type formed over the first semiconductor layer and having a doping concentration lower than that of the first semiconductor layer; (b) forming a trench in a second region of the multilayer substrate in which a power MISFET is to be formed; (c) forming a gate insulating film over an inner wall of the trench; (d) forming a gate electrode over the gate insulating film so as to fill the trench with the gate electrode; (e) forming a channel region of a second conductivity type opposite to the first conductivity type in the second region of the multilayer substrate; (f) forming, in the second region of the multilayer substrate, a source region contiguous to the trench and comprising a semiconductor region of the first conductivity type; (g) forming a first metal film which is contiguous to the source region in the second region of the multilayer substrate and which is contiguous to the second semiconductor layer to form a Schottky junction in a first region of the multilayer substrate in which a Schottky barrier diode is to be formed; and (h) forming a second metal film over a lower surface of the semiconductor substrate included in the multilayer substrate, wherein the first metal film serves as a source electrode of the power MISFET in the second region and serves as an anode electrode of the Schottky barrier diode in the first region, wherein the second metal film serves as a drain electrode of the power MISFET in the second region and serves as a cathode electrode of the Schottky barrier diode in the first region, and wherein, after completion of the power MISFET and the Schottky barrier diode, a boundary between the first semiconductor layer and the second semiconductor layer is present in a region as deep as or shallower than the bottom portion of the trench. - View Dependent Claims (21, 22, 23, 24, 25)
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Specification