Damage to Si substrates during SiO2 etching: A comparison of reactive ion etching and magnetron-enhanced reactive ion etching

The damage and contamination effects present in silicon substrates from both reactive ion etching and magnetron-enhanced reactive ion etching of SiO2 have been examined for various overetch percentages using spectroscopic ellipsometry (SE) and secondary ion mass spectroscopy (SIMS). The former method has shown that the thickness of the etch-induced heavy damage layer in silicon decreases, but its damage density increases with magnetic field. In addition, a thinner fluorocarbon residue layer was detected by both SE and SIMS on the samples etched in the presence of a magnetic field. The high temperature annealing behavior of silicon surfaces after UV/O2 removal of this polymer layer was also compared for samples etched with and without the presence of a magnetic field. Almost complete surface recovery was observed for the samples etched with the presence of a magnetic field as a result of a 15 min anneal at 600 °C.