Investigation of electronic noise in THz SiGe HBTs by microscopic simulation

Noise in an ultimate SiGe HBT with peak cutoff and maximum oscillation frequencies above 1THz is investigated by a microscopic transport model based on the Boltzmann equation, which can handle the quasi-ballistic transport, high frequencies and the complicated band structure in such devices. The noise performance of the transistor is excellent due to the high intrinsic speed. For example, the minimum noise figure can be as low as 0.7dB at 100GHz for this intrinsic device. A drawback of this device is the low collector/emitter breakdown voltage and above this voltage impact ionization degrades the noise performance.