| 摘要 |
PURPOSE:To increase the speed of operation of a bipolar transistor by forming a groove-shaped vertical hole directed toward a buried layer from the surface of a base body and shaping a reverse conduction type semiconductor layer into a semiconductor layer from the inner surface of the vertical hole through a diffusion. CONSTITUTION:An N<+> buried layer 2 is formed selectively to a P-type semiconductor substrate 1. An epitaxial layer 3 is shaped onto the substrate to which the layer 2 is formed. A groove-shaped hole 10 is shaped at a position where an emitter oppositely facing the layer 2 must be formed. A P-type impurity is diffused through a diffusion from the inner surface of the hole 10 and ion implantation from the surface of the substrate to shape a base layer 4 in a bipolar transistor. An oxide film 11 is formed onto an inner circumferential surface except the base of the hole 10, and the hole 10 is buried with polycrystalline Si to which phosphorus is doped. The impurity is diffused into the layer 4 from the bottom of the hole 10 by the burying to shape an emitter layer 5. Accordingly, the width (w) of a section adjacent to the layer 4 can be limited with excellent precision, thus sufficiently reducing the thickness (t) of a low-concentration collector layer 3, then attaining enough speeding-up.
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