Silicon carbide semiconductor device
First Claim
1. A process for producing a silicon carbide semiconductor device, comprising:
- a first step of laminating a first conductive type low-resistance semiconductor layer, a first conductive type high-resistance semiconductor layer, and a second conductive type first semiconductor layer in that order on top of one another to form a semiconductor substrate of a single crystal silicon carbide and forming a first conductive type semiconductor region in a predetermined region of the surface portion in the first semiconductor layer;
a second step of forming a trench extending through the semiconductor region and the first semiconductor layer into the high-resistance semiconductor layer;
a third step of forming a second semiconductor layer, formed of a single crystal silicon carbide, on at least the side face of the inner wall of the trench;
a fourth step of forming a gate oxide layer on the surface of the second semiconductor layer in the trench;
a fifth step of forming a gate electrode on the surface of the gate oxide film in the trench; and
a sixth step of forming a first electrode on the surface of the semiconductor region and optionally on the surface of the first semiconductor layer and forming a second electrode on the surface of the low-resistance semiconductor layer.
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Accused Products
Abstract
A silicon carbide semiconductor device having a high blocking voltage, low loss, and a low threshold voltage is provided. An n+ type silicon carbide semiconductor substrate 1, an n- type silicon carbide semiconductor substrate 2, and a p type silicon carbide semiconductor layer 3 are successively laminated on top of one another. An n+ type source region 6 is formed in a predetermined region of the surface in the p type silicon carbide semiconductor layer 3, and a trench 9 is formed so as to extend through the n+ type source region 6 and the p type silicon carbide semiconductor layer 3 into the n- type silicon carbide semiconductor layer 2. A thin-film semiconductor layer (n type or p type) 11a is extendedly provided on the surface of the n+ type source region 6, the p type silicon carbide semiconductor layer 3, and the n- type silicon carbide semiconductor layer 2 in the side face of the trench 9.
273 Citations
10 Claims
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1. A process for producing a silicon carbide semiconductor device, comprising:
- a first step of laminating a first conductive type low-resistance semiconductor layer, a first conductive type high-resistance semiconductor layer, and a second conductive type first semiconductor layer in that order on top of one another to form a semiconductor substrate of a single crystal silicon carbide and forming a first conductive type semiconductor region in a predetermined region of the surface portion in the first semiconductor layer;
a second step of forming a trench extending through the semiconductor region and the first semiconductor layer into the high-resistance semiconductor layer; a third step of forming a second semiconductor layer, formed of a single crystal silicon carbide, on at least the side face of the inner wall of the trench; a fourth step of forming a gate oxide layer on the surface of the second semiconductor layer in the trench; a fifth step of forming a gate electrode on the surface of the gate oxide film in the trench; and a sixth step of forming a first electrode on the surface of the semiconductor region and optionally on the surface of the first semiconductor layer and forming a second electrode on the surface of the low-resistance semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- a first step of laminating a first conductive type low-resistance semiconductor layer, a first conductive type high-resistance semiconductor layer, and a second conductive type first semiconductor layer in that order on top of one another to form a semiconductor substrate of a single crystal silicon carbide and forming a first conductive type semiconductor region in a predetermined region of the surface portion in the first semiconductor layer;
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9. A process for producing a semiconductor device using silicon carbide, comprising the steps of:
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preparing a silicon carbide substrate having a surface of a (0001) carbon face; forming a trench on the surface of the (0001) carbon face; forming a semiconductor layer on bottom and side surfaces of the trench; and thermally oxidizing the semiconductor layer such that the semiconductor layer formed on the bottom surface of the trench is entirely converted to an oxide layer while the semiconductor layer formed on the side surface of the trench is partially converted to an oxide layer to leave a thinned semiconductor layer interposed between the oxide layer converted from the semiconductor layer on the side surface of the trench and the side surface of the trench.
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10. A process for producing a MOS transistor, comprising the steps of:
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laminating a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type to provide a semiconductor substrate composed of silicon carbide and having a surface of a (0001) carbon face of the second semiconductor layer of the second conductivity type; forming a trench extending from the surface to the first semiconductor layer of the first conductivity type; forming a third semiconductor layer at least on the bottom and side surfaces of the trench; thermally oxidizing the third semiconductor layer such that the third semiconductor layer formed on the bottom surface of the trench is entirely converted to an oxide layer while the third semiconductor layer formed on the side surface of the trench is partially converted to an oxide layer as a gate oxide layer of a MOS transistor to leave a thinned third semiconductor layer as a channel region of the MOS transistor interposed between the oxide layer converted from the third semiconductor layer on the side surface of the trench and the side surface of the trench; and forming a gate electrode in the trench.
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Specification