SEMICONDUCTOR DEVICE AND MANUFACTURE THEREOF

摘要

PURPOSE:To realize a high-speed bipolar transistor by a method wherein a first semiconductor region to function as an external base and a second semiconductor region to function as an internal base are connected directly under an end part of an opening in an oxide film as an insulating film. CONSTITUTION:A thermal oxide film 122 having a beak-shaped end part is formed on the surface of an N-type epitaxial semiconductor layer 104 having an N-type buried layer 102 formed on a P-type silicon semiconductor substrate 100. The following are formed under a main part of this oxide film: a P-type semiconductor region 116 to function as an external base; a groove part 142 formed in an opening by this oxide film: a P-type semiconductor region 126 to function as an internal base in the lower part of this groove part. The external base 116 and the internal base 126 are connected directly under the beak- shaped end part of the oxide film; a polysilicon electrode 124 is formed in an N-type semiconductor region 128 to function as an emitter. By this setup, a structure of a high-speed active device part is obtained.