Cluster-based Quantum Chemical
Studies of Atomic Layer Deposition (ALD) of Al2O3 on H-Passivated
Silicon
Matthew Halls
Department of Chemistry
Indiana University
Due to the imminent failure of
SiO2 as a gate oxide layer as semiconductor device feature sizes
continue to decrease, there is a growing need for alternative high ?
dielectric materials. Aluminium oxide (Al2O3), deposited by atomic
layer deposition (ALD), is one of the most promising SiO2 replacement
materials under current investigation. The most often used precursors
for Al2O3 growth are trimethylaluminum (Al(CH3)3, TMA) and H2O, as the
aluminum and oxygen sources, respectively. In this talk, the
atomistic details and reaction energetics of the Al2O3 ALD process is
presented as determined by hybrid density functional theory. Si
cluster models have been used with appropriate boundary conditions to
investigate the initial surface reactions, competing side-reactions
and ALD growth reactions between TMA and H2O and the 2x1 reconstructed
hydrogen terminated Si(100) surface. Results obtained for Si(100) and
Si(111) are compared and implications for the interpretation of
experimental observations are discussed.