METHOD FOR MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE
First Claim
1. A method for manufacturing a silicon carbide semiconductor device, comprising the steps of:
- forming a silicon carbide substrate including a first layer having first conductivity type, a second layer provided on said first layer and having second conductivity type, and a third layer provided on said second layer, separated from said first layer by said second layer, and having said first conductivity type;
forming a trench provided with an inner surface having a side wall surface and a bottom surface, said side wall surface extending through said third layer and said second layer and reaching said first layer, said bottom surface being formed of said first layer;
forming a silicon film to cover said bottom surface;
forming a gate oxide film on said inner surface by oxidation in said trench, said gate oxide film including a first portion formed by oxidation of said silicon carbide substrate, and a second portion formed by oxidation of said silicon film on said bottom surface; and
forming a gate electrode on said gate oxide film.
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Abstract
A silicon carbide substrate including a first layer having first conductivity type, a second layer having second conductivity type, and a third layer having the first conductivity type is formed. A trench provided with an inner surface having a side wall surface and a bottom surface is formed, the side wall surface extending through the third layer and the second layer and reaching the first layer, the bottom surface being formed of the first layer. A silicon film is formed to cover the bottom surface. A gate oxide film is formed on the inner surface by oxidation in the trench. The gate oxide film includes a first portion formed by oxidation of the silicon carbide substrate, and a second portion formed by oxidation of the silicon film on the bottom surface. Accordingly, a method for manufacturing a silicon carbide semiconductor device having a high breakdown voltage is provided.
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Citations
8 Claims
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1. A method for manufacturing a silicon carbide semiconductor device, comprising the steps of:
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forming a silicon carbide substrate including a first layer having first conductivity type, a second layer provided on said first layer and having second conductivity type, and a third layer provided on said second layer, separated from said first layer by said second layer, and having said first conductivity type; forming a trench provided with an inner surface having a side wall surface and a bottom surface, said side wall surface extending through said third layer and said second layer and reaching said first layer, said bottom surface being formed of said first layer; forming a silicon film to cover said bottom surface; forming a gate oxide film on said inner surface by oxidation in said trench, said gate oxide film including a first portion formed by oxidation of said silicon carbide substrate, and a second portion formed by oxidation of said silicon film on said bottom surface; and forming a gate electrode on said gate oxide film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification