Noise model for the superconducting-base semiconductor-isolated transistor

A simple noise model for bipolar transistors is adapted to the Superconducting-Base Semiconductor-Isolated Transistor (SUBSIT). This model includes two statistically independent shot noise current sources in a lumped element model. For the case where the emitter of the SUBSIT is a normal metal, it is shown that the bipolar model carries over intact. For a SUBSIT with a superconducting emitter as well as base, the noise performance improves tremendously, due to the sharper turn-on characteristic. Noise temperatures in the milliKelvin regime are possible, and the energy resolution is likely to be quantum limited. © 1989 IEEE