| 摘要 |
A field controlled bipolar switch having a bulk single crystal silicon carbide substrate of a first conductivity type having an upper surface and a lower surface. A first epitaxial layer of a second conductivity type silicon carbide is formed upon the upper surface of the substrate. A second epitaxial layer of the second conductivity type silicon carbide is formed on the first epitaxial layer of silicon carbide. A plurality of regions of a third conductivity type silicon carbide are formed in the second epitaxial layer to form a gate grid in the second epitaxial layer. A third eptiaxial layer of the second conductivity type silicon carbide is formed on the second epitaxial layer and a fourth epitaxial layer of the second conductivity type silicon carbide is formed upon the third epitaxial layer. The fouth epitaxial layer has a higher carrier concentration than is present in the first, second and third epitaxial layers. A first ohmic contact is formed upon the fourth epitaxial layer and a second ohmic contact is formed on the lower surface of the substrate. An ohmic gate contact is connected to the gate grid for pinching off the flow of current between the first ohmic contact and the second ohmic contact when a bias is applied to the ohmic gate contact. |
