A double-layer uncooled thermistor infrared detector based on standard CMOS technology

作者：Shen Ning; Yu Jun; Huang Zheng Xing; Tang Zhen An^*

来源：Journal of Optoelectronics - Laser, 2014, 25(5): 845-850.

• Double layers
• Micromachining process
• Multi-sacrificial layers
• Standard CMOS technology
• Temperature coefficient of resistance
• Thermal time constants
• Thin-film depositions
• Uncooled infrared detectors

This paper develops a low-cost double-layer uncooled thermistor infrared detector based on standard 0.5 μm CMOS technology and micromachining processes. The double-layer infrared detector employs a hidden-bridge-leg micro-bridge structure with a 55 μm×55 μm bridge deck, two 7.5 μm width hidden bridge legs and an aluminum thermistor. The micro-bridge structure is implemented by the surface sacrificial layer technology without any additional lithography or thin film deposition procedure. The sacrificial layers include three materials: aluminum, tungsten and polysilicon. The double-layer infrared detector has a size of 65 μm×65 μm and a fill factor of 71.6%. The temperature coefficient of resistance (TCR) of the aluminum thermistor is about 0.419%/K in a muffle furnace whose temperature varies from 10°C to 100°C. The thermal conductance of the double-layer infrared detector is calculated as 1.96×10-5 W/K by measuring responses to different heating currents from 0.3 mA to 4.8 mA. The fabricated infrared detector is irradiated by an infrared laser which is modulated by a mechanical chopper in a frequency range of 10-1000 Hz. Measurements show that the thermal time constant is 1.14 ms and the thermal mass is 2.23×10-8 J/K. The responsivity of the infrared detector is about 2.54×104 V/W at 10 Hz and the calculated detectivity is 1.6×108 cmHz1/2/W.

• 出版日期2014