Picosecond large-signal switching characteristics of a pseudomorphic AlGaAs/InGaAs modulated doped field effect transistor

We present the first comprehensive study of the large‐signal switching characteristics of an AlGaAs/InGaAs modulation‐doped field‐effect transistor on a picosecond time scale. Electro‐optic sampling is used to measure drain voltage response to a steplike gate input with a 2.8 ps rise time, at various dc biases. A large‐signal switching time of 6.2 ps is obtained. Features deleterious to high‐frequency device operation are observed, related to equivalent circuit parameters, and reduced by appropriate choice of operating point.