Kelvin probe force microscopy for potential distribution measurement of cleaved surface of GaAs devices

Kelvin probe force microscopy (KFM) was successfully applied to the measurement of two-dimensional potential distribution of the cleaved surface of GaAs devices under bias voltage. It was shown that the voltage resolution is less than 10 mV. The measured potential profile of the ungated HEMTs shows a potential knee, which probably originates from the charge trapped at the interface between the epitaxial layer and the substrate. It also shows a potential ridge. which corresponds to the channel. Current crowding phenomena are also confirmed to occur at the edge of the drain electrode.