Low temperature analysis of 0.25 μm T-gate strained Si/Si/sub 0.55/Ge/sub 0.45/ n-MODFET's

Abstract

A low temperature dc and HF investigation of 0.25 /spl mu/m T-gate Si/Si/sub 0.55/Ge/sub 0.45/ n-MODFET's is presented. Outstanding maximum oscillation frequencies f/sub max/ range from 100-120 GHz at 300 K up to 195 GHz at 50 K. These high-frequency characteristics are the first reported at low temperature on Si/SiGe n-MODFET's and are also the highest room temperature data reported so far; physical modeling is used to explain the main trends observed when cooling down the n-MODFET. Many experimental data are presented. The dependence on temperature and biases of the important small-signal equivalent circuit parameters is investigated to analyze the device high-frequency performances and the minimum noise figure of the intrinsic device is determined.