Chemical regulation in the bonding reconstruction stage of amorphous Zr-Si oxidation and the resultant phase selection

Abstract

A mechanism based on oxidation induced bonding reconstruction (OBR) was proposed to optimize phase selection during oxidation of amorphous ZrxSi1−x (0.55 ≤ x ≤ 0.75). According to VASP modeling, a self-barrier effect was proposed to regulate the OBR and Zr/Si separation at initial oxidation stage. The depressed Si inner-diffusion leads to the formation of amorphous bilayer structure. A Si-rich Zr-Si layer formed underneath the outer Zr-Si-O amorphous layer, which synergistically impeded oxygen permeation at subcritical environment. As confirmed by EELS and XPS, the alternative of Zr-O and Si-O bonds in Zr-Si-O layer contributed to the enhanced hydro chemical stability.