Crystalline ternary rare earth oxide with capacitance equivalent thickness below 1nm for high-K application

Ternary neodymium-gadolinium oxide (NGO) thin films were grown epitaxially on Si(001) substrates using modified molecular beam epitaxy. The electrical properties of NGO thin films demonstrate that this ternary oxide could be one of the most promising candidates to replace the conventionally used SiO2 or SiOxNy in complementary metal oxide semiconductor devices. The films were characterized with various methods. The capacitance equivalent oxide thickness of 4.5nm thin films extracted from capacitance-voltage (C-V) characteristics was 0.9nm. For such films, leakage current density and the density of interface traps were 2.6×10−4A∕cm2 at ∣Vg−VFBV∣=1V and 1.4×1012∕cm2eV−1, respectively.