INFRARED SPECTROSCOPIC STUDY OF MERCURY-SENSITIZED PHOTO-CVD SILICON-OXIDE

Silicon oxide (SiOx) films deposited on a silicon wafer by the Hg–sensitized photochemical vapor deposition (photo-CVD) method using silane (SiH4) and nitrous oxide (N2O) under the illumination of low pressure mercury lamps were investigated. While increasing the partial pressure ratio of SiH4 to N2O, an increasing-maximum-decreasing behavior of the deposition rate and an increasing shape behavior of the refractive index have been observed. Infrared (IR) spectra analysis showed that the films were SiO2-like in the low silane partial pressure region and were SiO-like in the high silane partial pressure region. The 450 cm-1 absorption peak was good evidence for differentiating these two types of films. The infrared absorption peak due to Si–H stretching can also be eliminated after the N2 annealing treatment. © 1990 The Japan Society of Applied Physics.