Si dangling-bond-type defects at the interface of (100)Si with ultrathin HfO2

Abstract

Electron spin resonanceanalysis of (100) Si/HfO 2 interfaces prepared by chemical vapor deposition of the oxide using three chemically different precursors reveals that the trivalent Si defects common for Si/SiO 2 interfaces— P b0 and P b1 centers—are universally observed upon hydrogen detachment. The density of the P b0 is higher than in the (100) Si/SiO 2 structures and is sensitive to the deposition process. However, the density can be significantly reduced by annealing of the Si/HfO 2 structures in O-containing ambient, likely through re-establishing the Si/SiO 2 interface. Also, the P b -type centers can be entirely passivated by hydrogen already at 400 °C. The density of fast interface states closely follows the variations in the P b0 center density, suggesting it as the dominant contribution to the fast interface states.