| 摘要 |
PURPOSE:To prevent improper withstand voltage of a collector and an emitter of a semiconductor device by uniformly forming a base width without forming a groove at the boundary between a dielectric isolating layer and an element region. CONSTITUTION:An element region surrounded by a dielectric isolating layer 26' is formed by isolating via the dielectric a semiconductor substrate 21. Then, an insulating film 28 having an etching speed faster than the layer 26' is accumulated on the overall surface. Then, the first impurity region which is contacted with the layer 26' is formed at the element region before or after the step of forming the film 28. Then, the film 28 is photoetched, thereby forming an insulating pattern having a hole over parts of the first impurity region and the layer 26'. Subsequently, the second impurity region which has reverse conductive type to the region and which is contacted with the film 26' is formed in the first conductive type impurity region by a selective impurity doping with the insulating pattern as a mask. |
