| 摘要 |
PURPOSE:To enable always introduction of maximum reverse withstand voltage characteristics in a semiconductor device by forming a P-N junction in a semiconductor substrate, and then etching and removing in advance the surface of the substrate to form a protective film. CONSTITUTION:A P type region is formed on one main surface of an N type substrate 1, a main junction 2 and a guard ring junction 3 are annularly formed, and a protective film 4' of glass member is formed in the range containing the main junction 2 outside the junction 3. A protective film 4'' such as SiO2 is formed in the surface region in which the film 4' of the main junction 2 is not formed. The film 4' is formed by etching and removing the surface of the substrate wider than the range laterally extending under the surface of the substrate in the extension of a depletion layer when the maximum reverse withstand voltage in designing the diode is applied and filling and baking the glass member thereto. In this manner, the surface insulating breakdown by the charge storage in the boundary between the protective film such as SiO2 and the Si substrate can be prevented. |
