Atomic layer deposition of Al2O3 on H-passivated Si:: Al(CH3)2OH surface reactions with H/Si(100)-2X1 -: art. no. 161302

Infrared absorption studies of Al(CH3)(3) interacting with H-terminated Si reveal that O incorporation from gas-phase impurities may be a crucial factor in interface formation in atomic layer deposition. Hybrid density-functional calculations have therefore been carried out on silicon cluster models to investigate the possible pathways for reaction between the important atomic layer deposition side-reaction product Al(CH3)(2)OH (DMAOH) and the H/Si(100)-2x1 surface. Comparisons with the analogous surface reactions for Al(CH3)(3) and H2O are made. In general, the DMAOH surface reaction pathways are characterized by an activation of reactions involving the OH groups and suppression of CH3 group reactions, compared to Al(CH3)(3) and H2O. A unique reaction pathway for DMAOH and the H/Si(100)-2x1 surface is identified resulting in the deposition of -O-Al(CH3)(2) on the surface, which is significant since it represents an atomic-layer interface between Si and Al2O3. This reaction has an energy barrier of 1.3 eV and is the most thermodynamically favored pathway with an exothermicity of 0.9 eV.