High-performance p-n-p AlGaAs/GaAs heterojunction bipolar transistors: A theoretical analysis

The AlGaAs/GaAs P-n-p heterojunction bipolar transistor (HBT) is shown by a simple analysis to exhibit millimeter wave and digital switching performance comparable to similar N-p-n structures. For example, a P-n-p HBT with a 1-µm emitter stripe and 34-µm
²
total area yields
f_{\tau} = 31
GHz,
f_{\max} = 94
GHz, and an intrinsic switching speed
\tau_{s} = 8
ps. A similar N-p-n structure exhibits
f_{\tau} = 56
GHz,
f_{\max} = 102
GHz, and
\tau_{s} = 8
ps.