| 摘要 |
PURPOSE:To ensure a large electrical junction area by a small layout area and to reduce a serial parasitic resistance value by forming a Schottky barrier diode in a recess. CONSTITUTION:A square pyramidal-shaped recess 22 is formed by anisotropic etching, etc. in the part surrounded by a p type diffusion layer 30 which forms a base region. This recess 22 is formed in a manner the bottom of it goes into an epitaxial layer 12 under the p type diffusion layer 30 with leaving a slight distance (d) from a buried layer 14. Then metal M is put over the whole inner surface of the recess 22 and these are combined. Thus, the metal M is combined with the plane covering both of a base region and a collector region of a bipolar transistor Q1 and consequently, a Schottky barrier is formed between an epitaxial layer 12 of a relatively low impurity concentration. i.e. the collector region and the metal M. Because the junction part of the metal M and the semiconductor is formed along the inner surface of the recess 22, a layout area seen from the outside is small whereas a large junction area can be obtained in the shape of a cubic space. |
