| 摘要 |
PURPOSE:To enhance only a breakdown strength level of a device by a method wherein a first and a second regions whose conductivity type is opposite to that of a semiconductor substrate and whose concentration is higher than that of the substrate are formed separately on the semiconductor substrate to be concentrically ring-shaped and the first and the second regions are connected to each other via a resistor. CONSTITUTION:An impurity region 9 whose conductivity type is identical to that of a high-concentration impurity region 2 is formed to be ring-shaped in the circumference of the high-concentration impurity region 2 of a planar P-N junction in such a way that it surrounds this region by keeping a certain interval; these two impurity regions 2, 9 are connected by using a resistor 10. By this setup, a breakdown phenomenon of a device is first caused at a curvature part of a ring-shaped P-N junction at a voltage identical to that of a conventional structure; however, its electric current is suppressed to be low due to the resistor 10, and an increased portion of the voltage after that is held by a voltage drop of the resistor 10. When an impressed voltage reaches a breakdown voltage at the flat P-N junction part, a large breakdown current first flows to the whole device. By this setup, it is possible to enhance only a breakdown strength level without lowering other characteristics of the device. |
