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 TiO ₂ and Al ₂O ₃, with the two extremes of high permittivity (k) and high band offset, we produced a Ti _xAl _1-xO _y, (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 SiO ₂ or silicide interface formation. We demonstrated TAO layers with <0.5 nm 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.