Very high speed polysilicon emitter bipolar transistor and circuit

The fabrication of the very high speed polysilicon emitter bipolar transistor and circuit with double-layer polysilicon was reported. This kind of structure was improved in many aspects as compared with the single-layer polysilicon emitter bipolar transistor, especially in the vertical dry etching of the first polysilicon and the technology to form the multiple-dielectric-layer L-shaped sidewall, consisting of SiO2 and Si3N4 between the base and the emitter. It can reduce the base area of the bipolar transistor. The good DC and AC performance and cut-off frequency of 6.1 GHz were obtained in the emitter size of 3 ??m??8 ??m. The minimum gate delay of 19-stage ECL ring oscillator is 40 ps/gate and the maximum toggle frequency of a 2:1 static divider is 3.2 GHz.EI03345-3492