Microdischarge Optical Emission Spectroscopy as a Novel Diagnostic Tool for Metalorganic Chemical Vapor Deposition of (Ba,Sr)TiO3 Films

Microdischarge optical emission spectroscopy (µD-OES) was developed as a diagnostic tool for analyzing chemical reactions in metalorganic chemical vapor deposition of (Ba,Sr)TiO3 films. The degree of thermal decomposition of the CVD source molecules was obtained from the observed emission spectra of the small plasma excited at the OES sensor head. According to the observation of SrII and BaII emission lines, Sr(DPM)2 and Ba(DPM)2 decompose at the gas temperatures of 270°C and 280°C, respectively. The temperature dependence of the observed emission intensity showed a behavior similar to that of the deposition rate. The oxidation of the CVD source molecules in the gas phase was also investigated by observing the change in the emission spectra due to the addition of oxygen gas. We also measured the spatial distribution of the source molecules by radially moving the OES sensor head, and compared it with the uniformity of the film thickness.