Noise performance of Si/Si/sub 1-x/Ge/sub x/ n-channel HEMTs and p-channel FETs

Noise characteristics are evaluated for SiGe/Si based n-channel HEMTs and p-channel MOSFETs. The analysis is based on a self-consistent solution of Schroedinger and Poisson's equations. The model predicts a superior minimum noise figure for an n-channel HEMT at 77 K. p-channel MOSFETs behave similar to n-channel devices operating at 300 K. The minimum noise figure decreases with increasing quantum well (QW) width for both n- and p-channel devices. However, the p-channel devices are less sensitive to QW width variation. Minimum noise temperature behaves similarly. As observed, a range of doped epilayer thickness exists where the minimum noise figure is a minimum for both n- and p-channel FETs.