Oxidation behavior of chromium nitride films

Abstract

Chromium nitride (CrN) films were deposited onto (100) silicon using a commercially available cathodic arc plasma deposition system. Oxidation of the films was conducted in air at temperatures ranging from 650 to 850 °C for 2 h. X-ray diffraction spectra revealed that Cr2O3 diffraction peaks appeared above 650 °C and the relative integrated intensity of the oxide increased gradually with temperatures. Moreover, five vibration bands associated with Cr2O3 were discerned in Raman spectra above this temperature. Nano-granular structure showed up at 650 °C, while abnormal grain growth resulting from the grain coalescence occurred above 800 °C. A thin dense oxide overlayer was present at 650 °C and the oxide thickness increased gradually with temperatures. Meanwhile, underneath CrN grains grew drastically above 700 °C and became more equiaxially-grained at 850 °C. The pre-exponential factor and activation energy of oxidation for CrN films were evaluated by analyzing the Arrhenius relation from the temperature dependence of oxide thickness. The obtained values were 1.3×10−8 cm2/s and 110±6 kJ/mol, respectively, which is comparable to the literature data.