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Ab-initio study on the γ-Al<inf>2</inf>O<inf>3</inf> surfaces and interfaces

Abstract:

The controlled growth of alumina films by atomic layer deposition (ALD) is of great interest to the electronics industry, as high-k dielectrics are being sought for the next-generation of MOSFETS. We present a theoretical study of the alumina polymorph γ-Al2O3 based on density functional theory (DFT). The pbkp_redicted bulk structure for γ-Al 2O3 has the Al vacancy sites widely separated, which is in agreement with other theoretical pbkp_redictions. We estimated the energy of several γ-Al2O3 surfaces namely: (111), (110) and (110). The atomic and electronic structure of the most stable (111) surface is discussed and compared with α-Al2O3 (0001). The adsorption and dissociation of the H2O onto the (111) surface is considered and H-diffusion is simulated, Finally, a model for the γ-Al2O3 (111)/alummium-hydroxide interface is proposed and considered as an intermediate stage in the γ-alumina film growth mechanism.