Uncooled Infrared Bolometer Arrays with α-Si and Metal Films
A bolometer with stress equilibrium based on α-Si and metal films is proposed in this paper. The sensitive and support material α-Si films are prepared by plasma enhanced chemical vapor deposition（PECVD）, their stress and deposition rate are studied, and the technological parameter of the low stress and higher temperature coefficient of resistance (TCR) α-Si film are obtained. The result shows that the stress of the α-Si films can be adjusted between positive and negative. Pt films are deposited by electron-beam evaporating equipment. Their square resistance, TCR and stress are tested by four point resistivity test system and film-stress interferometer. The result shows this material is a good heat-sensitive material, and at the same time it can balance the stress of α-Si film. Finally it is found that Pt film is in compressive stress state in the selected technological parameters, and α-Si thin film is in tensile stress state, so the stress of micro-bridge structure can be balanced by this method. In the final, 160×120 infrared micro-bridge array on the wafer and read out integrated circuit (ROIC) chip are successfully fabricated.
Yuan Ming Huang
H. Liu et al., "Uncooled Infrared Bolometer Arrays with α-Si and Metal Films", Materials Science Forum, Vols. 663-665, pp. 421-424, 2011