MOS transistors with improved gate dielectrics

摘要

The specification describes silicon MOS devices with gate dielectrics having the composition Ta1-xAlxOy, where x is 0.03-0.7 and y is 1.5-3, Ta1-xSixOy, where x is 0.05-0.15, and y is 1.5-3, and Ta1-x-zAlxSizOy, where 0.7>x+z>0.05, z<0.15 and y is 1.5-3. By comparison with the standard SiO2 gate dielectric material, these materials provide improved dielectric properties and also remain essentially amorphous to high temperatures. This retards formation of SiO2 interfacial layers which otherwise dominate the gate dielectric properties and reduce the overall effectiveness of using a high dielectric material.