Si dangling-bond-type defects at the interface of (100)Si with ultrathin layers of SiOx, Al2O3, and ZrO2

Abstract

Electron spin resonance on (100) Si/SiO x / ZrO 2 and (100) Si/Al 2 O 3 / ZrO 2 stacks with nm-thin dielectric layers reveals the Si dangling-bond-type centers P b0 , P b1 as prominent defects at the (100)Si/dielectric interface. This P b0 , P b1 fingerprint indicates that, while gratifying for the Si/SiO x / ZrO 2 case, the as-deposited (100) Si/Al 2 O 3 interface is basically Si/SiO 2 -like. The interfaces are in an enhanced (unrelaxed) stress state, characteristic of low-temperature Si/SiO 2 growth. Based on the P b0 , P b1 criterion, standard thermal Si/SiO 2 interface properties may be approached by appropriate annealing (⩾ 650 °C) in vacuum in the case of Si/SiO x / ZrO 2 . Yet, O 2 ambient is required for Si/Al 2 O 3 , indicating that the initial abruptness of the interface prevents thermal adaptation to occur until an additional SiO x interlayer grows. A minimal SiO x interlayer thickness (≳0.5 nm) appears requisite.