Theoretical Study of the Mechanism for the Reaction of Trimethylaluminum with Ozone.

The mechanism for the reaction of trimethylaluminum (TMA, Al(CH3)3) with ozone (O3) was investigated in detail using density functional theory calculations to understand the atomic layer deposition processes that form aluminum oxide surfaces. We examined the reactions of TMA and some possible intermediates with O3 and revealed plausible paths to form methoxy (-OCH3), formate (-OCHO), bicarbonate (-CO3H), and hydroxyl (-OH) species. These species have been observed in previous experimental studies. It was shown that TMA easily reacts with O3 to generate the Al(CH3)2(OCH3)(O2) intermediate. The subsequent reaction between the OCH3 and O2 groups finally generated an intermediate having a formate group. When all of the CH3 groups are converted into OCH3 or OCHO, O3 will react with these groups. In the latter reaction, bicarbonate was shown to be formed.