MOBILITY STUDY ON RIE ETCHED SILICON SURFACES USING SF6 O-2 GAS ETCHANTS/

A methodology for the measurement of the inversion layer mobility on t rench gate structures, which allows independent measurement of the sid ewall and bottom surface mobilities, is described. Using this method, the inversion layer mobility has been experimentally studied for trenc hes formed using the SF6/O2 method on diffused base regions of power U MOSFET's for the first time. The effect of several post RIE surface tr eatments on the surface mobility is reported. The measured sidewall mo bilities have been found to be comparable to those previously reported for other RIE etchants. These results are of interest for the design of novel devices using the trench gate (UMOS) technology.