Atomic Layer Deposition (ALD) has been used to deposit TiO2 films on Si (100) and GaAs (100) surfaces from tetrakis dimethylamino titanium (TDMATi) and H2O at 200°C. The growth rate is measured at ~.6Å/cycle by High Resolution Transmission Electron Microscopy (HRTEM) and spectroscopic ellipsometry, and Rutherford Backscattering measurements indicate steady state Ti atom coverage of ~1.4x1015 cm-2. As deposited films are slightly overoxidized (O/Ti~2.2) and are amorphous, but inert anneals above 500°C result in film crystallization mainly in the rutile phase. When films are deposited on native oxide GaAs surfaces an interface cleaning reaction is observed. The starting surface consists of ~26Å of gallium and arsenic native oxides. X-ray photoelectron spectroscopy indicates that the surface oxides are consumed gradually during the ALD process and that after 120 and 250 process cycles only about a monolayer of metallic arsenic-arsenic suboxide and gallium suboxide persists at the interface and the conclusions are corroborated by HRTEM data. The results for the TiO2/GaAs interface will be compared to that obtained for the HfO2/GaAs interface using two different but similar ALD chemistries that utilize amide precursors (TEMAHf and TDMAHf). All three ALD chemistries indicate the presence of an “interface cleaning” mechanism similar to what has been observed for other amide-precursor-based ALD processes. [1] [2] [3]

[1] C.-H. Chang, Y.-K. Chiou, Y.-C. Chang, K.-Y. Lee, T.-D. Lin, T.-B. Wu, M. Hong, J. Kwo, Appl. Phys. Lett. 89, 242911 (2006)

 [2] C. L. Hinkle, A. M. Sonnet, E. M. Vogel, S. McDonnell, G. J. Hughes, M. Milojevic, B. Lee, F. S. Aguirre-Tostado, K. J. Choi, H. C. Kim, J. Kim, and R. M. Wallace, Appl. Phys. Lett. 92, 071901 (2008)

[3] J.C. Hackley, J.D. Demaree, and T. Gougousi, Appl. Phys. Lett. 92(16), 162902 (2008).