Growth Mechanisms of Aluminum Dots Deposited by Laser-induced Decomposition of Trimethylamine Alane

Aluminum dots have been deposited by thermal decomposition of trimethylamine alane (TMAA) on silicon substrates irradiated with a tightly focused argon ion laser beam (λ=514 nm). Carbon free Al deposits containing less than 5 at.% of impurities (mainly oxygen) detected by Auger Electron Spectroscopy were grown. The growth kinetics of Al dots was investigated as a function of TMAA pressure and laser-induced temperature. The deposition of dots occurred at a laser-induced temperature as low as 210°C. The TMAA decomposition was thermally activated (activation energy of 18 kcal/mole) and the deposition rate at 300°C was equal to 2 µm/s. The effects of H 2 or He (used as buffer gases) in the gas phase on the growth kinetics of dots was also studied. The growth mechanisms of dots are discussed and proposed on the basis of the results of this kinetic study.