Greatly Improved Interfacial Passivation Of In-Situ High Kappa Dielectric Deposition On Freshly Grown Molecule Beam Epitaxy Ge Epitaxial Layer On Ge(100)

A high-quality high-kappa/Ge interface has been achieved by combining molecule beam epitaxy grown Ge epitaxial layer and in-situ deposited high kappa dielectric. The employment of Ge epitaxial layer has sucessfully buried and/or removed the residue of unfavorable carbon and native oxides on the chemically cleaned and ultra-high vacuum annealed Ge(100) wafer surface, as studied using angle-resolved x-ray photoelectron spectroscopy. Moreover, the scanning tunneling microscopy analyses showed the significant improvements in Ge surface roughness from 3.5 angstrom to 1 angstrom with the epi-layer growth. Thus, chemically cleaner, atomically more ordered, and morphologically smoother Ge surfaces were obtained for the subsquent deposition of high kappa dielectrics, comparing with those substrates without Ge epi-layer. The capacitance-voltage (C-V) characteristics and low extracted interfacial trap density (D-it) reveal the improved high-kappa/Ge interface using the Ge epi-layer approach. (C) 2014 AIP Publishing LLC.