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

Abstract

The reaction of trimethylaluminum (Al(CH 3 ) 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(CH 3 ) 3 +H→AlH(CH 3 ) 2 +CH 3 and the activation energy for Al(CH 3 ) 3 +H→Al(CH 3 ) 2 +CH 4 are much smaller than the dissociation energy for radical decomposition, Al(CH 3 ) 3 →Al(CH 3 ) 2 +CH 3 . 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.