Atomic layer deposited (TiO_2)_x(Al_2O_3)_(1-x)/ln_(0.53)Ga_(0.47)As gate stacks for Ill-V based metal-oxide-semiconductor field-effect transistor applications

摘要

Atomic layer deposited (ALD) (TiO_2)_x(Al_2O_3)_(1-x)(TiAlO) alloy gate dielectrics on In_(0.47)Ga_(0.53)As/InP substrates are shown to produce high quality interfaces between TiAlO and InGaAs. The surface morphology and interfacial reaction of nanolaminate ALD TiAlO on In_(0.53)Ga_(0.47)As are studied using atomic force microscopy and x-ray photoelectron spectroscopy. Measured valence and conduction band offsets are found to be 2.85 ± 0.05 and 1.25 ± 0.05 eV, respectively. Capacitance-voltage characteristics show low frequency dispersion (~ 11%), interface state density (~4.2 x 10~11cm~-2eV~-1), and hysteresis voltage (～90 mV). Ga-O and As-O bonding are found to get suppressed in the gate stacks after post deposition annealing. Our experimental results suggest that higher oxidation states of In and Ga at the In_(0.53)Ga_(0.47)As surface and As diffusion in the dielectric are effectively controlled by Ti incorporation in Al_2O_3.