Electron spin resonance analysis of (100)Si/HfO2 interfaces prepared by chemical vapor deposition of the oxide using 3 chemically different precursors reveals that the trivalent Si defects common for Si/SiO2 interfaces—Pb0 and Pb1 centers—are universally observed upon H detachment. The density of the Pb0 was higher than in the (100)Si/SiO2 structures and was sensitive to the deposition process. However, the density could be significantly reduced by annealing of the Si/HfO2 structures in O-containing ambient, likely through re-establishing the Si/SiO2 interface. Also, the Pb-type centers could be entirely passivated by H already at 400C. The density of fast interface states closely follows the variations in the Pb0 center density, suggesting it as the dominant contribution to the fast interface states.

Si Dangling-Bond Type Defects at the Interface of (100)Si with Ultra-Thin HfO2. A.Stesmans, V.V.Afanasev: Applied Physics Letters, 2003, 82[23], 4074-6