Study on new structure uncooled a-Si microbolometer for infrared detection

A new structure uncooled amorphous silicon (a-Si) microbolometer for infrared (IR) detection has been fabricated and characterized. New type of thermal isolation and IR absorption structures based on polyimide (PI) and bottom metal reflective layer are presented. The fabrication process is described in this paper. The as-prepared microbolometer has the advantage of low cost, high yield and moderate performance. The dependence of resistance with different aspect ratio on operating temperature has been investigated and the temperature coefficient of resistance (TCR) is achieved. Based on the measured responsivity and noise characteristics, the influence of detectivity on chopping frequency is discussed. According to the measurements and calculations results, the maximal TCR is −2.8% and at a bias voltage of 5 V, the maximum detectivity of 1.7×108 cm Hz1/2 W−1 is achieved at chopping frequency of 30 Hz.