Control of interfacial silicate between HfO2 and Si by high concentration ozone

By high concentration ozone oxidation at low temperature, the Hf-silicate interfacial layer between HfO2 and silicon substrate is effectively controlled. This is evident by investigating the chemical shifts of the Hf4f and Si2p core-level spectra with depth by using x-ray photoelectron spectroscopy. The improved interfacial microstructure is further confirmed by high-resolution cross-sectional transmission electron microscopy. The capacitance-voltage curves, obtained from the metal-oxide-semiconductor capacitors using the ozone oxidized HfO2 as the gate dielectric, show a negligible hysteresis of about 5mV and a low fixed charge density.