| 摘要 |
PURPOSE:To construct a high breakdown strength MIS field-effect transistor which attains reduced on-resistance through high-integration while assuring sufficient breakdown strength of an element. CONSTITUTION:On a well layer 100 formed an the surface side of a semiconductor substrate 101, the first and second area parts 103 and 102, facing each other, with a part of the semiconductor substrate 101, selectively left as it is as a well non-formation area 101a, in between, separately exist. Since a flat protrusion-like base corner part, where electric field is easy to concentrate, of a base layer 105 is surrounded by the semiconductor substrate 101 and the first area part 103 that becomes depleted at a relatively low apply voltage, electric field concentration into this part is relaxed, so, with a smaller radius of curvature at a base corner part, higher integration and lower on-resistance of elements becomes possible, while high breakdown strength being kept. |
