Potential profile measurement of cleaved surface of GaAs HEMTs by Kelvin probe force microscopy

Kelvin probe force microscopy (KFM) was successfully applied to the measurement of two-dimensional potential profile of the cleaved surface of GaAs HEMTs under bias voltage. The measured depth profile of the potential shows potential knee which probably originates from the charge trapped at the interface between the epitaxial layer and the substrate. The high-field region is confirmed to be formed at the drain-side edge of the gate.