x-ray photoelectron spectroscopy analysis of the atomic layer deposition of AlOon SiO/Si: Interface dipole and persistent surface groups.

Atomic layer deposition (ALD) has become an essential technology in many areas. To better develop and use this technology, it is of the pivot to understand the surface chemistry during the ALD film growth. The growth of an ALD oxide film may also induce an electric dipole at the interface, which may be further tuned to modulate the flat band voltage for electronic device applications. To understand the associated surface chemistry and interface dipole formation process, we herein employ anx-ray photoelectron spectroscopy technique to study the ALD growth of AlO, from trimethylaluminum and HO, on the SiO/Si surface. We find that an electric dipole is formed at the AlO/SiOinterface immediately after the first AlOlayer is deposited. We also observe persistent surface methyl groups in the HO half-cycle during ALD, and the amount of the persistent methyls is particularly higher during the initial AlOALD growth, which suggests the formation of Si-CHon the surface. These findings can provide useful routes and insights toward interface engineering by ALD.