Study On The Resistance Characteristic Of Infrared Detection Materials

Currently, infrared detectors have broad application prospects in military and civilian fields. Bolometer is one of mainstream uncooled infrared detectors, which has advantages of light weight, wide dynamic range, excellent response linearity and without refrigeration and chopper which leads to low manufacturing cost.The core of bolometer is thermal sensitive materials, but applied to infrared thermal imaging detection are rarely reported. At present, the core of the infrared detector components are still completely imported from abroad. Therefore, only development of the thermal sensitive films with high TCR and the appropriate resistance value at room temperature, excellent reproducibility of the preparation and the process is compatible with microelectronic technology, can break the monopoly of foreign technology.Compared with the semiconductor material, metal with lower TCR when used as sensitive films, but have advantages of richer in material resources, wider linear range, low cost and compatibility with silicon integrated process excellently. In this paper, the thin film thermal resistor are deposited by DC magnetron sputtering at first, Ni, Ti, Al, Cr, TiW and Pt material with high purity (99.99%) are used, the resistance characteristics are measured by the four-probe tester, and then TCR are calculated. This paper focus on the influences of pressure, argon gas flow rate, sputtering power on the TCR of thin films. Experiments and test results showed that deposition and annealing process had major impact on film properties, Pt sensitive films have the best temperature sensitivity, stable performance through comparing the thermal properties of various metal materials. The optimal deposition annealing parameters are obtained that working pressure 0.8 Pa, argon gas flow rate 100 sccm, sputtering current 0.08 A, annealing time 2 hours, annealing temperature 300℃, then temperature coefficient of resistance (TCR) of platinum films with sheet resistance 1200Ω/□can be improved to 0.911‰/K which shows good repeatability and stable performance under this situation.