Nb5N6 thin film on silicon and silicon oxide: A good material for terahertz detection

Voltage responsivity of bolometer will benefit from high temperature coefficient of resistance (TCR) of the material. The Nb₅N₆ thin solid films we proposed in this paper have high TCR, compared with the commonly-used materials such as Nb and Bi. The films were sputtered on Si(100), SiO₂/Si(100), SiO₂ substrates by using radio frequency (r _f) magnetron sputtering. The deposition conditions have been optimized to get high TCR. The highest TCR is over 0.91% K⁻¹ at 300 K and up to 4.5% K⁻¹–7% K⁻¹ at 78 K, which is good enough to be used in terahertz detection and thermometer fabrication in the range from 78 K to 300 K.