Growth at moderate temperatures, below similar to 100 degrees C, is shown to prevent interfacial silicon oxidation during atomic layer deposition of high-permittivity (high-kappa) gate dielectrics on hydrogen-terminated Si(100). Trimethylaluminum, employed for aluminum oxide growth, leaves the hydrogen layer completely intact. Tetrakis(ethylmethylamido) hafnium partially scavenges the hydrogen layer during hafnium oxide nucleation, resulting in an interface composed of H-terminated silicon atoms and Si-O-Hf bridges. In both cases, high-kappa dielectrics are grown without formation of interfacial SiO2. Once grown at low temperatures, subnanometer Al2O3 layers effectively prevent interfacial SiO2 formation during subsequent growth at higher temperatures required for optimum high-kappa quality. This two-step deposition scheme may thereby be useful for gate- stack scaling. (c) 2007 The Electrochemical Society. [DOI: 10.1149/1.2405839] All rights reserved.