Review of Cernox™ (Zirconium Oxy-Nitride) Thin-Film Resistance Temperature Sensors

Abstract

Cernox™ resistance thermometers were commercially introduced in 1993. The Cernox™ temperature‐sensing element is fabricated from zirconium reactively sputtered in a nitrogen‐oxygen atmosphere. The resulting thin film is comprised of conducting zirconium nitride embedded within a zirconium oxide nonconducting matrix. This material has a negative temperature coefficient of resistance making it useful as a temperature sensor. The ratio of conducting to nonconducting material can be varied to tailor the sensor to a given temperature range. A single device can be fabricated for use from below 0.3 K to 420 K. Cernox™ temperature sensors possess many attributes desirable in a temperature sensor including high sensitivity, excellent short‐term and long‐term stability, small physical size, fast thermal response and small calibration shifts when exposed to magnetic fields or ionizing radiation. This paper presents a review of Cernox™ temperature sensors with regard to their physical, thermometric and operational properties and environmental effects.