| 摘要 |
PURPOSE:To increase the cut off frequency of a semiconductor device by providing two holes on a substrate, and deleting a P-N junction region having larger capacity of insulator of non-active regions as much as possible, thereby reducing the effective capacity. CONSTITUTION:An oxidized film 2 and a polysilicon 17a are formed on a P type semiconductor substrate 1, and two holes are opened by photolithography. In this case, the film 2 is etched excessively, and then ions are implanted in the film, and an N<+> type layer 3 becoming a collector is formed. Then, a polysilicon 17b is again deposited, and a thick oxidized film 18 is formed by dry etching. Subsequently, the film 18 and the polysilicon 17 are selectively etched, the polysilicon 17c is further selectively deposited. Then, the layer 3 is covered with resist, boron ions are implanted so that a P type layer 10 is connected in the substrate, and a channel cut 7 is formed. Similarly, the emitter 12 is formed, and base and collector electrodes 14, 16 are then formed. |
