| 摘要 |
PURPOSE:To decrease a writing current and to implement high integration density, by growing polysilicon on the base of a memory cell formed in a collec tor, opening a window, and forming an emitter through the window, in which the width is decreased due to the lateral expansion when the polysilicon is oxidized. CONSTITUTION:A part, which is to become a base region, is opened in an oxide film 8 on the surface of a semiconductor substrate in a collector region 5 that is electrically insulated. Thus a window 8a is formed. A silicon nitride film 9 is grown on the entire surface. Ions are implanted, and a P-type base region 6 is formed. Thereafter, polysilicon 10 is grown on the entire surface. A small window 10a is provided at a part on the base 6. When the polysilicon 10 is oxidized, the part of the window 10a is expanded in the lateral direction, and an oxide film 11 is obtained. A window 11a, which has a smaller width than the window 10a, is formed. The silicon nitride film 9, which is exposed at the window 11a, is etched away. Then polysilicon 12 is grown. Ions are implanted, and an n-type emitter 7 is formed by heat treatment. Thereafter the polysilicon is patterned in a specified shape, and a metal wiring 13 is formed thereon. |
