THERMAL-PROPERTIES OF A PYROELECTRIC-CERAMIC INFRARED DETECTOR WITH METALLIC INTERMEDIATE LAYER

Infrared thermal detectors were prepared with pyroelectric PSN-PT-PZ ( 1/47/52) ceramics, where a signal electrode had a structure Au/metalli c buffer/Pb(Zr,Ti)O-3 ceramic. The effect of a metallic buffer layer o n the voltage responsivity was investigated with a response to a step signal, made by a dynamic pyroelectric measurement. A pyroelectric cer amic wafer was prepared by a mixed-oxide technique. The Au layer (thic kness 50 nm) and the metallic buffers (thickness 0 to 20 nm) of Cr, Ni Cr (80:20), and Ti were prepared by do magnetron sputtering. In order to improve the light absorptivity, Au black was coated on the Au signa l electrode by thermal evaporation. A detector without a buffer layer showed a noisy and fluctuating output signal. Among the three kinds of buffer materials, NiCr (80:20) and Ti adhered well with ceramics and showed good electrical and thermal contacts, whereas Cr resulted in ba d contacts. Considering the output voltage and thermal properties, the optimum thickness of the buffer layer was about 15 to 20 nm, and sens ors with a Ti buffer 15 to 20 nm in thickness showed good detectivity. Thus, the stability and reliability of the infrared thermal sensors c ould be improved by using an appropriate buffer layer. (C) 1998 Societ y of Photo-Optical Instrumentation Engineers. [S0091-3286(98)02506-9].