Nanosized Potential Fluctuations in SiOx Synthesized by Plasma-Enhanced Chemical Vapor Deposition

Abstract

This work was devoted to studying the atomic structure and electron spectrum of a-SiO_x : H films created on silicon and glass substrates by means of plasma-enhanced chemical vapor deposition (PECVD). Depending on the conditions of oxygen supply into the reactor, the stoichiometric parameter x of the films was varied from 0.57 to 2. The structure of the films and the specific features of their electron structure were characterized depending on the parameter x with a complex of structural and optical methods and ab initio quantum-chemical simulation for the model SiO_x structure. The studied SiO_x : H films were established to consist predominantly of silicon suboxides SiO_y, SiO₂ clusters, and amorphous silicon. Based on the spatial fluctuations of their chemical composition, the model of bandgap width and potential fluctuations was proposed for SiO_x electrons and holes. The obtained data would provide the charge transport in a-SiO_x : H films with more precise modeling important for the creation of nonvolatile random-access memory (RAM) elements and memristors on their basis.