Characteristics of sputtered Hf1−xSixO2∕Si∕GaAs gate stacks

Sputtered Hf1−xSixO2∕Si∕n-type GaAs gate stacks with x=0, 30%, and 47% have been characterized using x-ray photoelectron spectroscopy, photoluminescence, and capacitance-voltage (CV) measurements. Incorporating Si into HfO2 improves both frequency dispersion and hysteresis. Compared to HfO2, 30% and 47% Hf1−xSixO2 have a lower interface state density and stronger photoluminescence intensity. At the same capacitance equivalent thickness, HfO2 and 30% Hf1−xSixO2 have a smaller leakage current density than 47% Hf1−xSixO2. It is concluded that Hf1−xSixO2 with the composition near 30% is a good high-k dielectric candidate for metal-oxide-semiconductor device application.