Determination of mobility in modulation-doped FET's using magnetoresistance effect

A simple measurement technique based on the magnetoresistance effect is developed to obtain the differential and average mobilities of modulation-doped field-effect transistors (MODFET's) with respect to gate bias voltage. The effect of parasitic series resistances can be neglected by using a low magnetic field. The measurement is not affected by parasitic gate capacitance and therefore constitutes an effective tool for characterizing fully processed ultra-short gate-length MODFET's.