Noise measure of GaAs and InP transferred electron amplifiers

The noise figures of GaAs and InP transferred electron amplifiers are first calculated for the artificial situation where the time-independent electric field and free carrier concentration are spatially uniform. This calculation, which included diffusion damping of the forward travelling space charge wave, predicted a minimum noise measure of about 7 dB for GaAs with nl product of about 40 billion per sq cm and of about 2 dB for InP with nl product of about 50 billion per sq cm. Noise measures were then calculated by computer simulation for realistic doping profiles, yielding values of 7 dB for GaAs and 4.5 dB for InP when both diffusion and shot noise are taken into account.