DENSITY FUNCTIONAL THEORY MOLECULAR DYNAMICS SIMULATIONS AND EXPERIMENTAL MEASUREMENTS OF A-HFO_2/A-SIO/SIGE(001) AND A-HFO_2/A-SIO_2/SIGE(001) INTERFACES

摘要

To determine the optimal interface between a-HfO_2 oxide and Si_(0.5)Ge_(0.5)(001), density functional theory molecular dynamics (DFTMD) simulations of several amorphous stoichiometric and sub-stoichiometric SiOxNy interlayers (a-SiO_(0.8)N_(0.8), a-SiO_(0.4)N_(0.4), a-Si_3N_2, a-Si_3N_4, a-SiO, and a-SiO_2,) were performed. In general the sub-stoichiometric interlayers had superior electrical properties because they minimized Ge-O and Ge-N bond formation and had low internal bond strain. The stack with oxygen deficient a-SiO interlayer demonstrated superior electric properties because it avoided all dangling bond formation. Experimental studies confirmed that a nearly pure SiOx interface between a-HfO_2 and SiGe(001) could be formed which correlated with a low interface state density.