Theoretical and Experimental Optimization of InGaAs Channels in GaAs PHEMT Structure

The ground-state energy level (GEL) and electron distribution of GaAs pseudomorphic high-electron-mobility transistors (PHEMTs) are analyzed by a self-consistent solution to the Schrodinger—Poisson equations. The indium composition and thickness of the InGaAs channel are optimized according to the GEL position. The GEL position is not in direct proportion to 1/d2 (d is the channel thickness) by considering the influence of electron distribution in the InGaAs channel. Indium composition 0.22 and channel thickness 9nm are obtained by considering the mismatch between InGaAs and AlGaAs. Several PHEMT samples are grown according to the theoretical results and mobility 6300 cm2/Vs is achieved.