Surface photochemical phenomena in laser chemical vapor deposition Available to Purchase

The role of surface adsorbate photochemistry in laser assisted Al film growth by photodecomposition of trimethylaluminum is investigated using a pulsed optoacoustic apparatus. The technique permits in situ measurements of the vibrational spectra of surface adsorbates on single crystal sapphire even under the ambient pressures typical of laser chemical vapor deposition. We characterize the initial sapphire surface and follow the nucleation and growth of photodeposited films to obtain a microscopic understanding of the growth mechanism. We show that high quantum yield nonthermal photodesorption of methyl groups from growth surfaces occurs with 193 nm irradiation and can be used to produce Al films of higher quality. Features of the vibrational spectra are shown to be correlated with macroscopic properties of metallic films grown under the same conditions and can be used to identify and evaluate the parameters important to high quality film growth.