Characteristics of Thin-Film NTC Infrared Sensors
Characteristics of thin-film NTC infrared sensors fabricated by micromachining technology were studied as a function of the thickness of membrane. The overall-structure of thermal sensor has a form of Au/Ti/NTC/SiO<I><SUB>x</SUB></I>/(100)Si. NTC film of Mn<SUB>1.5</SUB>CoNi<SUB>0.5</SUB>O<SUB>4</SUB> with 0.5 \\micron in thickness was deposited on SiO<I><SUB>x</SUB></I> layer (1.2 \\micron) by PLD (pulsed laser deposition) and annealed at 600–800°C in air for 1 h. Au (200 nm)/Ti (100 nm) electrode was coated on NTC film by dc sputtering. By the results of microstructure, X-ray and NTC analysis, post-annealed NTC films at 700°C for 1 h showed the best characteristics as NTC thermal sensing film. In order to reduce the thermal mass and thermal time constant of sensor, the sensing element was built-up on a thin membrane with the thickness of 20–65 \\micron. Sensors with thin sensing membrane showed the good detecting characteristics.
- Materials transactions
Materials transactions 43(5), 1065-1068, 2002-05-01