| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a fast bipolar transistor only by a mask alignment method which is usually used by forming an inverse electric conduction type emitter area on the surface of an exposed epitaxial layer and forming an electrode which comes into contact with a base area and an emitter area. SOLUTION: A heat treatment is carried out so as to round the corner parts of the opening surface of a contact hole. At the same time, impurities are diffused from a polysilicon film 19 to a 1st diffusion area 15 and an emitter area 8 is formed. A nitride film and an oxide film in a base contact area and a collector contact area are etched away to expose an N type epitaxial layer, and a polysilicon film for an electrode is formed over the entire surface. Then patterning is carried out to form an emitter electrode 10, a base electrode 11, and a collector electrode 12. In the base area, a heavily doped impurity diffusion area 21 for a contact may be formed.</p> |
