To increase complementary metal oxide semiconductor (CMOS) device performance, new materials are introduced in the gate stack (high-k dielectrics and metal gates) and the transistor channel (Ge, III-V materials). In this work we study the atomic layer deposition (ALD) of hafnium oxide on Ge and GaAs substrates. Passivation layers are required to achieve a sufficiently low interface state density, but these might also influence the growth behavior and dielectric quality. Therefore, we investigate the effect of surface preparation, for example, native oxide, wet clean, thermal oxidation, and S-passivation, for the HfCl4/H2O and tetrakis diethylamino hafnium=((C2H5)(2)N)(4)Hf (TDEAH)/H2O processes. The growth of HfO2 from initial submonolayer coverage to continuous HfO2 film is studied by means of Rutherford backscattering, static time-of-flight secondary ion mass spectroscopy, and X-ray photoelectron spectroscopy. HfCl4/H2O ALD depends on the surface preparation. The growth is enhanced on oxide surfaces (thermally grown GeO2, HF-cleaned Ge, and GaOx-AsOy) and inhibited on oxide-free substrates (HBr-cleaned Ge). The initial island growth regime is least pronounced on germanium oxide. In contrast, TDEAH/H2O ALD is independent of the surface preparation. The growth is inhibited in the first similar to 20 cycles on native oxide and S-passivated GaAs [(NH4)(2)S treatment], but the initial island growth regime is quickly followed by the two-dimensional growth regime. (c) 2008 The Electrochemical Society. [DOI: 10.1149/1.2979144] All rights reserved.