| 摘要 |
PURPOSE:To implement high withstanding voltage in a semiconductor integrated thyristor, by providing a reverse-conductivity type high resistance semiconductor layer having a thick step part, providing the gate region of the thyristor, whose conductivity is the same as that of a substrate at the thick part of said layer, and providing the anode region of said thyristor at the thin part of the layer. CONSTITUTION:A voltage is applied between an anode region 4 and a substrate 1 and a gate region 3. Then, depletion layers 6 and 7 are formed at the junction region between the substrate 1 and an epitaxial layer 2. The depletion layer 7 on the side of the epitaxial layer 2 is expanded upward, i.e., toward the side of the surface, at a step part, where the epitaxial layer 2 changes from the thick part to the thin part. At the same time, a depletion layer 8 is formed at the junction between the gate region 3 and the epitaxial layer 2 in the vicinity of the surface by the potential of the gate region 3. The depletions layer 7 merges with the depletion layer 8. Thus the depletion layers 7 and 8 on the side of the epitaxial layer 2 form the surface with a small curvature. Therefore, the concentration of an electric field in the epitaxial layer 2 is alleviated, and high withstanding voltage is further increased. |
