Abstract

An in situ investigation of thermal decomposition reactions of trimethylindium (TMIn) in a vertical, upflow chemical vapor deposition reactor has been carried out using Raman spectroscopy. Monomethylindium (MMIn) and atomic indium were detected along with the precursor TMIn using N₂ as the carrier gas. Atomic indium was identified by the peak at 2215 cm⁻¹, which is equal to the difference between two spin–orbit split levels of atomic indium in the ground electronic state. The multiple peaks corresponding to MMIn, which were enhanced by a resonance Raman effect, consisted of fundamentals(ν₂ = 1097 cm⁻¹,ν₃ = 430 cm⁻¹,ν₅ = 1364 cm⁻¹, ν₆ = 696 cm⁻¹) and a high progression of overtones and combination bands. Concentration profiles were obtained from the measurements of peak intensities of TMIn, MMIn, and indium at different distances away from the hot susceptor along the vertical centerline of the reactor.