Efficiency of oxygen plasma cleaning of reactive ion damaged silicon surfaces

Abstract

It is demonstrated with the use of in situ x-ray photoemission spectroscopy, secondary ion mass spectrometry, and transmission electron microscopy, that the commonly practiced in situ oxygen plasma/hydrofluoric acid dip treatment of reactive ion damaged silicon surfaces is insufficient in removing all reactive ion etching (RIE) related contaminants and damage. For CHF3/CO2 RIE the residual modifications are shown to be fluorine and carbon contamination and deeper lying modifications, e.g., hydrogen-induced extended Si defects. An enhanced silicon oxidation rate during air exposure has been observed for post-RIE-treated silicon, which correlates to the amount of residual fluorine.