Diffusion reaction of oxigen in aluminum oxide films on silicon

Abstract

Aluminum oxide films deposited on silicon by atomic layer chemical vapor deposition were annealed in an ¹⁸O-enriched oxygen atmosphere under various conditions of temperature, time, and pressure. Cavity formation at the film surface was monitored by atomic force microscopy and it was seen to depend on annealing parameters. Areal densities and profiles of oxygen incorporated from the gas phase were determined by nuclear reaction techniques. A propagating front of incorporated oxygen from the gas/solid interface toward the film/ substrate interface was observed. This was modeled as a diffusion-reaction process, where isotopic exchange is the reaction channel. The model is capable of reproducing the observed ¹⁸O profiles and areal densities as well as their dependence on annealing parameters.