| 摘要 |
PURPOSE:To provide a semiconductor device at high speed and of compact size by isolating the active region thereof with an oxide film to reduce a parasitic capacity thereof. CONSTITUTION:An N<+>-type buried layer 32 is diffused in a P-type Si substrate 31, an N-type epitaxial layer 33 is superimposed thereon, is isolated laterally with a P-type layer 36, an Si3N4 mask 301 is formed thereon, the layer 33 is etched to form eaves at the end of the mask 301. Then, it is coated with a thermal oxide film 37, and metal 302 is evaporated thereon. The oxide film 37 at the eaves is removed, the mask 301 is removed, and a doped polysilicon layer 38 is selectively formed to form an external base layer 38. Subsequently, the film 301, the film 38 and the film 39 are lifted off to form a P-type internal base layer 34 by diffusion. Subsequently, it is thermally oxidized to oxidize the external base layer 34', and an N-tye emitter 35 is formed. Thereafter, electrodes are provided at the collector layer and the base layer as predetermined to complte it. The active region of this device is formed in raised shape, and is isolated with an oxide film 34' to reduce the parasitic capacity, to enable high speed operation, and to reduce the power consumption with reduced occupying area. |
