The interfacial characteristics of high-κ ZrO2 on O2 and N2O-plasma-treated Si0.69Ge0.3C0.01 surfaces have been investigated using secondary ion mass spectroscopy and x-ray photoelectron spectroscopy. N2O-plasma-treated films show the formation of a nitrogen-rich Zr–germano–silicate interfacial layer between the deposited ZrO2 and SiGeC films. The N-treated film has a higher accumulation capacitance (∼1200 pF), lower leakage current density (7×10-9 A/cm2@-1 V), higher breakdown field (∼11 MV/cm), and higher interfacial layer dielectric constant (∼10) than that of the non-nitrogen-treated films. Relatively lower positive trap charge generated by a constant current stressing in N-incorporated dielectric films makes it attractive for scaled metal–oxide–semiconductor field-effect transistor applications. © 2003 American Institute of Physics.