| 摘要 |
PURPOSE:To increase impurity concentration in an emitter region and make the gradient of impurity concentration in an emitter-base junction steep, and to improve a current amplification factor by coating the emitter region with a silicon nitride film and thermally treating the whole. CONSTITUTION:A silicon oxide film layer 4 is formed on the surface of an n type epitaxial layer 2 shaped on a p type substrate 1, and the ions of a p type impurity are implanted into an emitter region and a collector region while using a photo-resist layer 11 as a mask. The resist layer 11 is removed, a silicon nitride film 12 is formed, and the film 12 is removed with the exception of the upper section of the emitter region. When the whole is thermally treated in an oxidizing atmosphere, impurity concentration in the emitter region is high because the intrusion of oxygen is prevented by the film 12 in the emitter region, and diffusion depth is also made smaller than the collector region. Accordingly, the gradient of impurity concentration in an emitter-base junction in made steep, and a current amplification factor is increased. |
