Real-Time Evaluation of Aluminum Borohydride Trimethylamine for Aluminum Chemical Vapor Deposition

The chemical species in gas phase and on the surface of aluminum borohydride trimethylamine (ABHTMA) for aluminum chemical vapor deposition as a function of the hot-wall temperature and the chamber pressure were studied using two kinds of Fourier transform IR spectroscopes installed at the end of the chamber. The absorbance of Al-H, B-H, C-H, and C-N stretching features of ligands in ABHTMA in the gas phase and on the surface was sensitive to the variation of analysis conditions. The area ratio of integrated absorbance of Al-H and B-H stretching features located at the different position could estimate the dissociation rate of the ABHTMA, which was abruptly changed in the range of 140-160 degrees C. With these results, the temperature dependence of the film composition and quality could be explained. Additionally, the stabilities of the chemical species were investigated using density functional theory calculations. The ABHTMA was found to be the most stable molecule when trimethylamine was rich and borane and alane were close in their concentrations. Borane-trimethylamine was also found to be produced in alane-poor conditions as a by-product. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3089355] All rights reserved.