Hot-carrier effects on radio frequency noise characteristics of LDD n-typemetal-oxide-semiconductor field effect transistors

Hot-carrier damage is a major issue in the long-term reliability of metal-o xide-semiconductor field effect transistors (MOSFETs), Hot-carrier induced damages have been shown to degrade various MOSFET characteristics-threshold voltage, channel charge mobility, parasitic drain and source resistances, and parasitic drain capacitance. The degradation induces changes in the sma ll-signal s parameters of MOSFETs. Further experimental results indicate th at such damages also degrade the radio frequency (rf) noise characteristics of a LLD n-type MOSFET (NMOSFET). The minimum noise figure (NFmin,) and th e normalized noise resistance (r(n))-two key noise parameters--increase due to hot-carrier stress. The optimal reflection coefficient (Gamma(opt)) ver sus frequency curve also changes with increase stressing. The degradation i n the rf noise characteristics of the LDD NMOSFET implies a serious issue i n designing reliable, low-noise rf circuits with MOSFETs. (C) 2000 American Vacuum Society. [S0734-2101(00)07402-9].