Molecular beam epitaxy grown template for subsequent atomic layer deposition of high κ dielectrics

摘要

Molecular beam epitaxy (MBE) grown high k dielectrics of Al_2O_3 and HfO_2 are employed as templates to suppress effectively the oxide/Si interfacial layer formation during the subsequent atomic layer deposition (ALD) growth. The absence of the interfacial layer was confirmed using x-ray photoelectron spectroscopy and high resolution transmission electron microscopy. Two composite films consisting of ALD Al_2O_3(1.9 nm)/MBE v(1.4 nm) and ALD Al_2O_3(3.0 nm)/MBE HfO_2(2.0 nm) showed overall κ values of 9.1 and 11.5, equivalent oxide thicknesses of 1.41 and 1.7 nm, D_(it) of 2.2 x 10~(11) and 2 x 10~(11) cm~(-2) eV~(-1), and leakage current densities of 2.4 x 10~(-2) A/cm~2 at V_(fb)-1 V and 1.1 x 10~(-4) A/cm~2 at V_(fb)+1 V, respectively. The attainment of high dielectric constant suggests that there is no low k capacitor in series near the oxide/Si interface.