Title :
Characteristic of thin-film NTC thermal sensors
Author :
Lee, Moonho ; Yoo, Mina
Author_Institution :
Dept. of Appl. Electron., Yeungnam Univ., Kyongsan, South Korea
Abstract :
The characteristics of thin-film negative temperature coefficient of resistance (NTC) thermal sensors fabricated by micromachining technology were studied as a function of the thickness of the membrane. The overall structure of the thermal sensor has the form of Au/Ti/NTC/SiOx/(100)Si. An NTC film of Mn1.5CoNi0.5O4 with 0.5 μm thickness was deposited on the SiOx layer (1.2 μm) by PLD (pulsed laser deposition) and annealed at 600-800°C in air for 1 hr. Au (200 nm)/Ti (100 nm) electrode was coated on the NTC film by DC sputtering. From the results of microstructure, X-ray and NTC analysis, post-annealed NTC films at 700°C for 1 hr showed the best characteristics as an 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 μm. Sensors with a thin sensing membrane show good detection characteristics.
Keywords :
annealing; infrared detectors; membranes; micromachining; pulsed laser deposition; sputter deposition; thin film devices; 0.5 micron; 1 h; 100 nm; 20 to 65 micron; 200 nm; 600 to 800 degC; Au-Ti-Mn1.5CoNi0.5O4-SiO-Si; Au/Ti/NTC/SiOx/(100)Si structure; DC sputtering; IR detector; NTC analysis; PLD; X-ray analysis; annealing; detection characteristics; membrane thickness; micromachining technology; microstructure analysis; negative temperature coefficient of resistance; post-annealed NTC films; pulsed laser deposition; thermal mass reduction; thermal time constant reduction; thin-film NTC thermal sensors; Biomembranes; Gold; Micromachining; Optical pulses; Pulsed laser deposition; Sensor phenomena and characterization; Temperature sensors; Thermal resistance; Thermal sensors; Thin film sensors;
Conference_Titel :
Sensors, 2002. Proceedings of IEEE
Print_ISBN :
0-7803-7454-1
DOI :
10.1109/ICSENS.2002.1036987
