A 62.8 GHz fmax LP-CVD epitaxially grown silicon base bipolar transistor with extremely high early voltage of 85.7 V

Abstract

Optimization of fmax and VA values was investigated by changing Wcpi and NB Values of low temperature LP-CVD epitaxial base. It was found that there are optimum conditions which can realize concurrent extremely high fmax value-more than 50 GHz-and extremely high Vn value-more than 50V-in the case of silicon epitaxial base bipolar transistors with silicided emitter and base electrodes. Relatively flat profile of boron in the epitaxial base region can realize high Vn value with high fmax. NiSi emitter and base electrodes technology can further increase the fmax value. The highest fmax value of 62.86 Hz at a collector current of 1.7 mA was achieved. High BVCBO of 4.7 V, high VA of 85.7 V and low p/sub BI/ value of 8.5 k/spl Omega//sq were also realized at the same time.