A comparison of Si and Si/sub 1-x/Ge/sub x/ based BJTs using numerical simulation

Static and small signal performances of Si and Si/sub 1-x/Ge/sub x/ based bipolar junction transistors (BJTs) are compared using numerical simulation. Si/sub 1-x/Ge/sub x/ BJT shows reduced turn-on voltage ( Delta V/sub BE/=0.12 V), much higher current gain h/sub fe/, up to two time higher unity current gain frequency f/sub T/, and somewhat higher maximum frequency of oscillation f/sub max/. By using Si/sub 1-x/Ge/sub x/ it is possible to reduce power dissipation in the circuit environment. Small signal current gain, as obtained by using the quasi-static approximation, is shown for the common emitter configuration.<
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