The authors report on interface characteristics of ZrO2 high-k gate dielectrics on Ge epitaxial layers integrated on Si substrates. For surface passivation, thermal desorption of Ge native oxide and Ge nitridation processes is applied to epitaxial Ge capacitor layers. Metal-oxide-semiconductor capacitors exhibit excellent electrical characteristics with a gate leakage current density of 6 x 10(-7)-1 x 10(-6) A/cm(2) with a capacitance equivalent thickness of 1.5-1.3 ran at a gate voltage of I V Thermal behavior of Ge native oxide and niftided Ge layers is correlated with electrical characteristics. (C) 2007 Elsevier B.V All rights reserved.