Chromium oxide thin film with well-defined crystallinity was successfully deposited using an unbalanced magnetron sputtering process. Binding energy measurement of Cr 2p(3/2) showed a good agreement with the theoretical Cr2O3 ESCA spectrum. Substrate bias voltages affected the lattice orientation with a clear Cr2O3 (006) texture occurred at a bias voltage of -70 V. Excessive thermal stress resulted in cracking of Cr2O3 exposed to high temperatures. The thermally-grown Cr2O3, oxidized from both CrN and Cr2N, showed great mechanical integrity with high thermal stability. Higher hardness of Cr2O3 can be obtained at the OEM setting of 35% and bias voltage of -120 V.