Electrical and ellipsometric characterization of the removal of silicon surface damage and contamination resulting from ion beam and plasma processing

Abstract

The silicon surface damage resulting from low-energy Ar ion beam and plasma bombardment under a variety of bombardment conditions has been measured and compared. Techniques used to characterize the damage and its removal included x-ray photoelectron emission spectroscopy and reflection ellipsometry to determine the type of incorporated impurities and the damage layer depth, respectively; and high-frequency and quasistatic capacitance-voltage measurements of interface trapped and fixed oxide charge to determine the electrical nature of the damage. While the ellipsometrically measured damage could be removed using various described treatments, the electrical damage persisted. Both electrical and optical differences resulting from lattice damage versus impurity-related damage associated with the different dry etching environments could be discerned.