Ab Initio Molecular Orbital Study on the Reaction of Trimethylaluminum with an H Radical

The reaction of trimethylaluminum (Al(CH3)3, TMA) with an H radical has been investigated using ab initio molecular orbital calculations. It has been shown that the reaction energy for Al(CH3)3+H→AlH(CH3)2+CH3 and the activation energy for Al(CH3)3+H→Al(CH3)2+CH4 are much smaller than the dissociation energy for radical decomposition, Al(CH3)3→Al(CH3)2+CH3. This means that H radicals easily break Al-C bonds. Therefore, it is suggested that H radicals, which come from hydride group-V sources, play an important role in the reduction of unintentional carbon incorporation into layers grown from alkyl group-III materials.