A VERY SMALL BIPOLAR-TRANSISTOR TECHNOLOGY WITH SIDEWALL POLYCIDE BASE ELECTRODE FOR ECL-CMOS LSPS

Very small, high-performance, silicon bipolar transistors (SPOTEC) wer e developed for use in ECL-CMOS LSI's, The transistors are fabricated with a sidewall polycide base; chemical vapor deposition is used to se lectively deposit tungsten on the sidewall surface of the polysilicon base, The tungsten is then silicided, This self-aligned polycide techn ology makes a narrow (0.4-mu m wide), low-resistance (7 Omega/square) base electrode possible, Narrow U-groove isolation and narrow collecto r metallization techniques are used to reduce the transistor area to 1 0 mu m(2). A shallow E-B junction and base layer have now been formed by using rapid-vapor-phase doping, The resulting transistors have good I-V characteristics without leakage current or high current gain, The y have a high cut-off frequency of 37 GHz (53 GHz with pedestal collec tor ion implantation and thin epitaxial layer) and small junction capa citances, These transistors will facilitate the development of very-hi gh-speed, high-density ULSI's.