High ε gate dielectrics Gd2O3 and Y2O3 for silicon

Abstract

We report on growth and characterization of both epitaxial and amorphous films Gd2O3 of (ε=14) and Y2O3(ε=18) as the gate dielectrics for Si prepared by ultrahigh vacuum vapor deposition. The use of vicinal Si (100) substrates is key to the growth of (110) oriented, single-domain films in the Mn2O3 structure. Typical electrical leakage results are 10−3 A/cm2 at 1 V for single domain epitaxial Gd2O3 and Y2O3 films with an equivalent SiO2 thickness, teq of 15 Å, and 10−6 A/cm2 at 1 V for smooth amorphous Y2O3 films (ε=18) with a teq of only 10 Å. For all the Gd2O3 films, the absence of SiO2 segregation at the interface is established from infrared absorption measurements.