In this paper, we present the fabrication and characterization of sputter deposited thin-film Cr-CrOx-Cr MIM diodes for application in millimeter wave detectors. The oxide layers were grown by thermal oxidation of the first deposited Cr electrode at 300 °C and at atmospheric pressure. The appreciable nonlinearity shown by these diodes confirms their viability in millimeter wave and infrared applications. The fabricated MIM structures exhibited sensitivity as high as 2.58 V−1 at Vbias of 0.3 V. Additionally, numerical integration of Simmons tunneling equations were utilized to extract the MIM diodes parameters. The correlation between the extracted parameters, the diodes performance and the fabrication conditions would be very valuable to effectively design and fabricate structures with improved performance.