The scavenging kinetics of an ultra-thin SiO2 interface layer (SiO2-IL) in an HfO2/SiO2/Si stack is discussed by focusing on the substrate effect in addition to oxygen diffusion. 18O tracing experiments demonstrate that the O-atom moves from the SiO2-IL to the HfO2 layer during scavenging. SiO2-IL scavenging with various substrates (Si, SiC, and sapphire) has been found to be significantly different, which suggests that the Si in the substrate is also necessary to continuously cause the scavenging. Based on these findings and thermodynamic considerations, a kinetic model where oxygen vacancy (VO) transferred from the HfO2 reacts with the SiO2, which is in contact with the Si-substrate, is proposed for the SiO2-IL scavenging.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)