Velocity overshoot of inversion layer electrons and holes is studied e
xperimentally and analytically in special test structures with nominal
ly uniform electric field. The data were used to calibrate energy rela
xation parameters in a commercial simulator MEDICI ver. 2.0. We propos
e an analytical model for velocity overshoot and show that it agrees w
ell with experimental data. The amount of hole velocity overshoot is s
mall. (C) 1997 Elsevier Science Ltd.