High Breakdown Voltage InAlAs/InGaAs High Electron Mobility Transistors on GaAs with Wide Recess Structure

Both an off-state breakdown voltage between a gate and a drain (B V gd) and maximum frequency of oscillation (f max ) are described as functions of the width of gate recess in an InAlAs/InGaAs high electron mobility transistor (HEMT), using a new analysis model. The model suggests that the wide recess structure can improve both B V gd and f max , which is experimentally confirmed. We fabricated InAlAs/InGaAs HEMTs lattice-mismatched to GaAs substrates with optimum recess width, and these exhibited both a high B V gd of 14 V and a high f max of 127 GHz at a gate length of 0.66 µm.