Study of ultrathin silicon oxide films by FTIR‐ATR and ARXPS after wet chemical cleaning processes

Abstract

AbstractThe narrowest feature on current integrated circuits is the gate oxide—the thin dielectric layer that forms the basis of field effect device structures. Silicon dioxide is the dielectric of choice and, if the present miniaturization trend continues, the projected oxide thickness will be <1 nm in 2005. Therefore, ultrathin silicon oxide layers using various preparation conditions have been studied by angle‐resolved x‐ray photoemission spectroscopy (ARXPS) and Fourier transform infrared attenuated total reflection (FTIR‐ATR).The silicon oxides obtained by wet chemical treatments such as RCA (SC1 + SC2), SC1 (standard clean), RHO3 (RCA + HF + O3) and DDC (diluted dynamic clean) are characterized in terms of chemical oxide quality before and after thermal annealing. The presence of suboxides (SiOx), as revealed by XPS results, is correlated with Ox–Si–H bonds observed by FTIR‐ATR. The FTIR‐ATR spectra, deconvoluted into four peaks in the asymmetrical stretching SiO bond region (1000–1200 cm−1), show differences between all these chemical oxides. The AS1 (in phase) and AS2 (out of phase) vibrations are compared in terms of position and intensity. The influence of thermal annealing on the chemical oxide quality is also presented. Copyright © 2002 John Wiley & Sons, Ltd.