Interfacial microstructure and electrical properties of HfAlOx thin films on compressively strained Si83Ge17 grown by RF magnetron sputtering

Interfacial microstructure and electrical properties of HfAlOx films deposited by RF magnetron sputtering on compressively strained Si83Ge17/Si substrates were investigated. HfSiOx-dominated amorphous interfacial layer (IL) embedded with crystalline HfSix nano-particles were revealed by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy depth profile study. About 280 mV-wide clockwise capacitance–voltage(C–V) hysteresis for the HfAlOx film deposited in Ar + N2 mixed ambient was observed. Oxygen vacancies and interfacial defects in the HfSiOx IL, as well as trapped charges in the boundaries between the HfSix nano-particles and surrounded amorphous HfSiOx may be responsible for the large C–V hysteresis.