Characterization of Reactive Ion Etched Silicon Surface by Deep Level Transient Spectroscopy

Abstract

The surface defects introduced on silicon surfaces by reactive ion etching are characterized by analyzing the pulse‐height dependence of DLTS spectra, in which the transient response of the occupation of carriers in discrete levels is taken into account by using the Fermi‐Dirac distribution function in the calculation. The material used as the cathode table is shown to be a source of the contaminants on the reactive ion etched silicon (RIE‐Si) surface, and a correlation between the characteristics of electron traps and the cathode material is found. A model of the surface region of RIE‐Si substrate is proposed, which includes an interfacial layer on the substrate and a damaged region near the top surface containing carrier traps. The calculated value of about 200Å for the thickness of the damaged region shows good agreement with measured thicknesses of about 300Å for the case of RIE using polyimide‐coated cathode.