Combined XPS, SIMS, and AFM analyses of silicon nanocrystals embedded in silicon oxide layers

Abstract

Silicon nanocrystals (Si-ncs) embedded in a dielectric matrix (e.g. Si 3N4, SiO2) attract significant interest for their use in silicon-based devices such as memories, light amplifiers, and light emitting diodes. Si-ncs in an SiO2 matrix are generally obtained through thermal annealing of silicon-rich oxide (SRO) at elevated temperatures (900-1200 °C). In this study, we have investigated the composition of annealed SRO layers close to the interfaces with Si3N4, or c-Si with XPS, SIMS, and atomic force microscopy (AFM). The analyses indicate an approximately 2-nm thick Si-depleted region close to both the Si 3N4 and c-Si interface formed after annealing at 1050°C. The formation of this Si-depleted layer is of importance for both electrical transport and charge storage in annealed SRO. Copyright © 2008 John Wiley & Sons, Ltd.