The noise measure of GaAs and InP transferred electron amplifiers

The noise measures of both GaAs and InP transferred electron amplifiers (TEA's) are calculated by a small-signal computer simulation for devices having a range of realistic doping profiles, some of which are designed specifically to limit the amount of free charge injected into the structure. Optimum values of average electric-field strength and carrier concentration times length product for minimum noise are shown to exist. The computed results differ not too greatly from those predicted by a simple analytical model where a uniform free carrier concentration and dc electric field are assumed. The lowest noise measures predicted are 7 dB for GaAs and 4 dB for InP if charge injection is suitably constrained. The computed results are compared with results reported in the literature.