MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To prevent the failure caused by contact of polysilicon layers by removing the insulating film on the second conductive-type region and forming a polysilicon layer after covering the polysilicon for electrode which is connected to the first conductive-type layer with the oxide film which is continuous from over the second conductive-type region. CONSTITUTION:An n type Si substrate 1 is oxidized to form an oxide film 2 which is then coated by an Si nitride film 3. A two-layer film 2 in a contact region of the first conductive-type layer is removed and a polysilicon layer 4 is formed. The substrate is doped with boron and is oxidized to form an oxide film 5. Then the Si nitride film 3 on the second conductive-type layer is removed. A second conductive-type layer 6 is formed by diffusion of boron at a time when the polysilicon 4 is oxidized. The oxide film 2 is removed and an oxide film 10 is formed by oxidation. The oxide film 10 on the second conductive-type layer is removed and a first conductive-type layer 7 is formed. The layer 7 is coated with polysilicon 11 in which arsenic is diffused so as to form a second conductive-type layer 9. Then it becomes possible to completely prevent contact of the polysilicon layers 4 and 11 which are connected with the first and second conductive-type layers respectively.