Hybrid titanium–aluminum oxide layer as alternative high-k gate dielectric for the next generation of complementary metal–oxide–semiconductor devices

Research is focused on finding reliable high-dielectric constant (k) oxides with high capacitance and all critical properties required for the next generation of complementary metal–oxide–semiconductor (CMOS) gates. A trade-off between dielectric constant and band-offset height is generally observed on gate oxides. Combining TiO2 and Al2O3, with the two extremes of high permittivity (k) and high band offset, we produced a TixAl1−xOy (TAO) oxide layer with k=∼30 and low dielectric leakage for a next generation of high-k dielectric gates. We developed a low temperature oxidation process, following room temperature sputter-deposition of TiAl layers, to produce ultrathin TAO layers on Si with subatomic or no SiO2 or silicide interface formation. We demonstrated TAO layers with <0.5nm equivalent oxide thickness on Si and thermal stability under rapid thermal annealing up to about 950°C. The data presented here provide insights into fundamental physics and materials science of the TAO layer and its potential application as gate dielectric for the next generation of CMOS devices.