A new time-of-flight technique for the study of transport velocities of electron packets under high tangential ( E T ) and normal ( E N ) electric fields in silicon surface inversion layers is described. Room temperature drift velocities at (100)Si-SiO 2 interfaces are reported for E T between (0.25 and 4.0) × 10 4V/cm and E N between (0.3 and 2.0) × 10 5V/cm. A surface drift velocity near saturation of 8.5 × 10 6cm/s is found at E T = 4.0 × 10 4 V/ cm and E N = 0.8 × 10 5 V/ cm,which is about 50% larger than obtained in the most recent comparable work.