A novel room-temperature rnicrobolometer array chip consisting of an Nb5N6 thin film microbridge and a dipole planar antenna,which is used as a terahertz (THz) detector,is described in this paper.Due to the high-temperature coefficient of the resistance of the Nb5N6 thin film,which is as high as-0.7％ K-1,such an antenna-coupled microbolometer is ideal for detecting signals in a frequency range from 0.22 THz to 0.33 THz.The dc responsivity,calculated from the measured Ⅰ-Ⅴ curve of the NbsN6 microbolometer,is about-760 V/W at a bias current of 0.19 mA.A typical noise voltage as low as 10 nV/Hz1/2 yields a low noise equivalent power (NEP) of 1.3 × 10-11 W/rHz1/2 at a modulation frequency above 4 kHz,and the best RF responsivity,characterized using an infrared device measuring method,is about 580 V/W,with the corresponding NEP being 1.7 × 10-11 W/Hz1/2.In order to further test the performance of the Nb5N6 microbolometer,we construct a quasi-optical type receiver by attaching it to a hyperhemispherical silicon lens,and the result is that the best responsivity of the receiver is up to 320 V/W.This work could offer another way to develop a large scale focal-plane array in silicon using simple techniques and at low cost.
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