Semiconductor device having trench structure
First Claim
1. A semiconductor device having a trench structure, comprising:
- a semiconductor substrate having a main surface and a rear surface;
a trench having sidewalls and a rectangular planar shape formed at the main surface of said semiconductor substrate;
an insulating layer formed to extend from the inner surface of said trench onto the main surface of said semiconductor substrate;
an impurity implantation region selectively formed around the upper end portion of the sidewall of the trench and surrounding one end of the trench in the elongate direction; and
a conductive layer formed on said insulating layer filling the trench and extending from the inside of said trench onto the impurity implantation region from the one end of the trench in the elongate direction and onto the main surface of said semiconductor substrate, whereinthe thickness of said insulating layer positioned on an upper end corner portion of a sidewall of said trench covered by said conductive layer and on the impurity implantation region is larger than the thickness of said insulating layer positioned on the sidewall of said trench excluding said upper end corner portion, and the semiconductor device exchanges signals between the main surface and the rear surface of the semiconductor substrate.
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Accused Products
Abstract
A trench is formed on a main surface of a p+ type monocrystalline silicon substrate. A silicon oxide film is formed extending from the inner surface of trench onto the main surface of p+ type monocrystalline silicon substrate. The thickness of a corner portion positioned on the upper end corner portion of the sidewall of trench in silicon oxide film is larger than the thickness of silicon oxide film positioned on the sidewall of trench. An n type polycrystalline silicon layer extending from the inside of trench onto the main surface of p+ type monocrystalline silicon substrate is formed on silicon oxide film. Thus, a semiconductor device having a trench structure with an improved breakdown voltage for an insulating layer positioned on an upper end corner portion of the sidewall of a trench is obtained.
181 Citations
14 Claims
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1. A semiconductor device having a trench structure, comprising:
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a semiconductor substrate having a main surface and a rear surface; a trench having sidewalls and a rectangular planar shape formed at the main surface of said semiconductor substrate; an insulating layer formed to extend from the inner surface of said trench onto the main surface of said semiconductor substrate; an impurity implantation region selectively formed around the upper end portion of the sidewall of the trench and surrounding one end of the trench in the elongate direction; and a conductive layer formed on said insulating layer filling the trench and extending from the inside of said trench onto the impurity implantation region from the one end of the trench in the elongate direction and onto the main surface of said semiconductor substrate, wherein the thickness of said insulating layer positioned on an upper end corner portion of a sidewall of said trench covered by said conductive layer and on the impurity implantation region is larger than the thickness of said insulating layer positioned on the sidewall of said trench excluding said upper end corner portion, and the semiconductor device exchanges signals between the main surface and the rear surface of the semiconductor substrate. - View Dependent Claims (2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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3. A semiconductor device having a trench structure, comprising:
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a semiconductor substrate having a main surface; a trench formed at the main surface of said semiconductor substrate; an insulating layer formed to extend from the inner surface of said trench onto the main surface of said semiconductor substrate; and a conductive layer formed on said insulating layer and extending from the inside of said trench onto the main surface of said semiconductor substrate, wherein the thickness of said insulating layer positioned on an upper end corner portion of a sidewall of said trench covered by said conductive layer is larger than the thickness of said insulating layer positioned on the sidewall of said trench excluding said upper end corner portion, and wherein the upper end corner portion of the sidewall of said trench is recessed. - View Dependent Claims (4)
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Specification