NOISE PERFORMANCE OF SI SI1-XGEX FETS

Noise characteristics are evaluated for SiGe/Si based n-channel MODFET 's and p-channel MOSFET's, The analysis is based on a self-consistent solution of Schrodinger and Poisson's equations. The model predicts a superior minimum noise figure for an n-channel MODFET at 77 K. P-chann el MOSFET's behave similar to n-channel devices operating at 300 K. Mi nimum noise figure decreases with increasing quantum well (QW) width f or both n- and p-channel devices. However, the p-channel devices are l ess sensitive to QW width variation. Minimum noise temperature behaves similarly. As observed, a range of doped epilayer thickness exists wh ere minimum noise figure is a minimum for both n- and p-channel FET's.