Studies of Silicon Oxynitride Films Produced by Radio-Frequency Plasma Assisted Electron Cyclotron Resonance

Abstract

AbstractSingle crystal silicon wafers were treated by direct oxynitridation using electron cyclotron resonance (ECR) and radio-frequency (rf) plasma with separate N2 and O2 gas sources. Fabricated layers were characterized by ex situ spectroscopic ellipsometry (SE), Auger electron spectroscopy (AES), and atomic force microscopy (AFM).The thickness and nitride/oxide ratio of silicon oxynitride layers were found to be dependent on the main process variables, namely gas pressure, bias voltage, and N2/O2 flow rate ratio. It was also observed that ECR/rf plasma is more efficient for the formation of layers with higher nitrogen content at relatively low pressure (≤ 200 mTorr) and bias voltage (−40 V) when compared to that of rf plasma alone. SE modeling provided good fitting to experimental data, while AES and AFM analyses supported SE results. The effects of fabrication conditions on the thickness and composition of the layers will be presented.