Research About Fabrication Process And Device Performance Of Linear Pyroelectric Detector

Due to the advantages of room temperature operation, wide spectra response, simple structure and low cost, terahertz(THz) detector based on pyroelectric material received dramatic attentions of domestic and global research in recent years. lithium tantalate(LT) has the merits of stable chemical and physical properties, unharmfulness, high curie temperature and appropriately high figure of merits, making it suitable for THz radiation detection. This paper focused on the following aspects.First, thermal and mechanical properties of LTbased pyroelectric detector were simulated by changing its geometrical structures. The results showed that the thicknesses and supporting arm widths have great effects on device performance such as highest temperature rise thermal response time and deformance of the detector.Second, thinning and polishing techniques of LT crystals respectively by wet and dry chemical etch were studied. For the wet etch, the impacts of parameters such as temperature, oxidant and pH on the etch rate of LT were systematically studied, the optimal etch condition was consequently obtained. To furthur improve surface quality of LT crystal, dry etch by reacitvie ion etch(RIE) method was applied, the optimal parameters to obtain smooth surface of LT was achieved.Third, the fabrication of THz absorption layer was studied to improve the weak absorption of the LT crystal in THz region. Carbon nanotube(CNT) was chosen as the absorption material due to its excellent properties. During the preparation process, two precursor solvent for the CNT, eg., epoxy resin, polyurethane were studied. Absorption test results showed that the absorption layer spin-coated by CNT+polyurethane mixture solution produced the best results of more than 40% absortption in THz region.Finally, a 32-elements LT based THz linear detector was prepared according to results of above study. Voltage responsivity, noise equivalent power(NEP) and uniformity of responsivity of the detector were tested to be 2786 V/W, 2.95×10-9 W/Hz1/2 and 91.6%, respectively, showing good performance of the fabricated smaple at room temperature.