In situ monitoring of the etching of thin silicon oxide films in diluted NH4F by IR ellipsometry

Infrared spectroscopic ellipsometry (IRSE) was applied to monitor the etching process of electrochemically formed silicon oxides (11.5 and 3.8 nm thick films) in diluted NH4F solution. The optical properties of the amorphous silicon oxide film and the time dependent thicknesses of the oxide films during the etching process were deduced from quantitative evaluations of IRSE spectra.