Formation processes of Ge3N4 by radical nitridation and electrical properties of Pr-oxide/Ge3N4/Ge structure were investigated. Stoichiometric Ge3N4 is Successfully formed by the radical nitridation at temperatures from 50 to 600 degrees C. Change in the nitridation temperature dependence of the saturated thickness of the Ge3N4 suggests different dominant diffusion species. Leakage current density through the Ge3N4 is minimized at a nitridation temperature of 300 degrees C. The XPS analyses of the Pr-oxide/Ge3N4/Ge suggest decomposition of Ge3N4 during atomic layer deposition of the Pr-oxide and formation of Pr-oxynitride at the Pr-oxide/Ge interface. An interface state density in the Al/Pr-oxide/Ge3N4/Ge capacitor is drastically reduced by forming gas annealing. (C) 2009 Published by Elsevier B.V.