Interaction of Di-Methylaluminum Groups with Hydroxyl Groups on a Fully Hydroxyl-Terminated Si (001) Surface

The interaction of -Al(CH3)(2) with -OH on a fully OH-terminated Si (001) surface was studied using density functional theory. Two sites for Al(CH3)(3) to react with the -OH on the surface were identified. The -Al(CH3)(2) product energetically favored the dimer-row site rather than the inter-row site because the Al atom of -Al(CH3)(2) at the dimer-row site was attracted by the lone pair electrons of the O atom in the neighboring -OH. The energy barrier for the transfer of the -Al(CH3)(2) between the two sites was 0.11 eV, and therefore, the -Al(CH3)(2) at the inter-row site can easily transfer to the dimer-row site at room temperature.