Improved growth behavior of atomic-layer-deposited high- k dielectrics on multilayer MoS₂ by oxygen plasma pretreatment

We report on the effect of oxygen plasma treatment of two-dimensional multilayer MoS₂ crystals on the subsequent growth of Al ₂O₃ and HfO₂ films, which were formed by atomic layer deposition (ALD) using trimethylaluminum and tetrakis-(ethylmethylamino) hafnium metal precursors, respectively, with water oxidant. Due to the formation of an ultrathin Mo-oxide layer on the MoS₂ surface, the surface coverage of Al₂O₃ and HfO₂ films was significantly improved compared to those on pristine MoS₂, even at a high ALD temperature. These results indicate that the surface modification of MoS₂ by oxygen plasma treatment can have a major impact on the subsequent deposition of high-k thin films, with important implications on their integration in thin film transistors.