Hysteresis in metal insulator semiconductor structures with high temperature annealed ZrO2/SiOx layers

Hysteresis behaviour in sandwich structure — zirconium oxide/chemical silicon oxide, annealed at temperature of 850 °C in oxygen ambient, was studied. Formation of thin ZrSi_xO_y layer due to the high temperature annealing was found. Metal-insulator-semiconductor (MIS) capacitors using ZrO₂/ZrSi_xO_y/SiO_x insulator were studied. High-frequency capacitance-voltage (HF C-V), current-voltage (I-V) and current-time (I-t) measurements were carried out on the Al/ZrO₂/ZrSi_xO_y/SiO_x/Si capacitors.Two leakage current components were identified — tunneling current component at high electric fields and transient current component at low fields. The transient leakage currents are due to charge trapping phenomena. The measured I-t characteristics are related with charging/discharging and dielectric relaxation phenomena. A counter-clockwise HF C-V hysteresis, larger than 2 V at thickness of the stack structure of about 50 nm was observed.Metal-insulator-semiconductor field effect transistors (MISFETs) using ZrO₂/ZrSi_xO_y/SiO_x-gate insulator were studied. P-channel MISFETs with aluminum gate electrode were fabricated on standard n-type silicon substrates. Due to charging/discharging phenomena in the gate dielectric the transistors can be switched between On- and Off-state with the polarity of applied stress voltage.