On Distributions of Defect States in Low-k Carbon Doped Silicon Dioxide Films in Vicinity of Fermi Level

Abstract

Spectrum of defect states N(E) in vicinity of Fermi level position in carbon-doped hydrogenated silicon dioxide (SiOCH) low-k films has been experimentally studied by deep level transient spectroscopy (DLTS) and space charge limited current (SCLC) techniques. The SiOCH films were deposited by CVD, using 3-methylsilane-oxygen mixture. Good correlation is found between features of defect spectrum obtained by DLTS and the SCLC techniques for the same SiOCH samples. In particular, N(E) peaks at 0.15-0.20 and 0.25-0.30 eV below E c have been detected by both techniques. These peaks are attributed to doubly negatively charged silicon vacancy in hexagonal or rhombohedral SiC-like phases.