Geometry-dependent low-frequency noise variations in 120 GHz f/sub T/ SiGe HBTs

The influence of aggressive geometrical scaling on the variation of low-frequency noise in 120 GHz peak f/sub T/ UHV/CVD SiGe HBTs is presented for the first time. The noise variation shows a strong dependence on transistor geometry and little dependence on bias conditions. Our previous noise theory is used to understand this behavior, and a comparison is made between these new results and our prior results on 90 GHz peak f/sub T/ generation SiGe technology.