ROLE OF FLUORINE IN REACTIVE ION ETCHING OF SILICON DIOXIDE

Thermal desorption from 15 keV, fluorine positive ion (F+)-implanted S iO2 has been studied using thermal desorption and X-ray photoelectron spectroscopies. Primary fluorine-related outgassing species SiF3+, gas eous O2, and a great amount of water evolution representing the SiO2 n etwork modification were observed. From comparatively well-investigate d desorption spectra from NF3/Ar reactive-ion-etching (RIE)-exposed an d CF4/Ar RIE-exposed SiO2, similar outgassing species and the desorpti on temperatures were observed. The desorption states for SiF3+ were no t single as previously reported in the study of desorption states rela ted to the thermal reaction with fluorocarbon polymer, but several des orption pathways existed. The observed similarity for SiF3+ is conside red to be related to the induced microstructural changes, which possib ly determine the final desorption path in RIE.