Suppression of parasitic Si substrate oxidation in HfO2-ultrathin-Al2O3-Si structures prepared by atomic layer deposition -: art. no. 252110

We investigated the effects of Al2O3 thickness on the suppression of parasitic substrate oxidation in HfO2-ultrathin-Al2O3-Si structures. The use of H2O as oxidizing agent in the atomic layer deposition (ALD) chemistry is considered key to preventing the formation of an SiOx interlayer during oxide deposition. An Al2O3 layer prepared with 10 cycles of atomic layer deposition (ALD, similar to 0.74 nm) effectively suppressed substrate oxidation during rapid thermal annealing in N-2 for 10 s below 800 degrees C. Parasitic oxidation was observed at 600 degrees C for samples with only five cycles or without Al2O3. Ultrathin Al2O3 films can be relevant for the integration of HfO2 as gate dielectric in silicon technology. (c) 2005 American Institute of Physics.