Fully strained Si0.75Ge0.25 epitaxial films with HfSiO gate dielectrics for high mobility channel metal-oxide semiconductor devices

The authors report on fully strained Si"0"."7"5Ge"0"."2"5 metal-oxide-semiconductor capacitors with HfSiO"2 high-k gate dielectric and TaN metal gate fabricated on Si substrates. Fully strained Si"0"."7"5Ge"0"."2"5 films are directly grown on Si substrates below the critical thickness. HfSiO"2 high-k gate dielectrics exhibit an equivalent oxide thickness of 13-18A with a permittivity of 17.7 and gate leakage current density lower than SiO"2 gate oxides by >100x. Interfacial oxide of the HfSiO"2/Si"0"."7"5Ge"0"."2"5 stack consists primarily of SiO"2 with a small amount of Ge and Hf. High performance SiGe field effect transistors are highly manufacturable with excellent electrical characteristics afforded by the fully strained HfSiO"2/SiGe gate stack.