Microbolometer with a salicided polysilicon thermistor in CMOS technology

Area of Science:

• Materials Science
• Electrical Engineering
• Infrared Technology

Background:

• Metal-type microbolometers in CMOS technology face challenges with low resistivity and high thermal conductivity.
• These limitations hinder their performance and restrict their application scope in infrared imaging.

Purpose of the Study:

• To demonstrate a novel polysilicon microbolometer fabricated using 0.18 µm CMOS and post-CMOS processes.
• To address the performance limitations of existing microbolometer technologies.

Main Methods:

• Fabrication of a microbolometer using polysilicon thermistors and a SiO2 absorber.
• Characterization of the microbolometer's electrical and thermal properties, including resistivity and thermal conductivity.
• Experimental evaluation of responsivity and detectivity for a 40 µm × 40 µm pixel.

Main Results:

• Achieved high resistivity (1.37×10^-4 Ω·cm) and low thermal conductivity (18 W/m·K) with the salicided poly-Si thermistor.
• Demonstrated maximum responsivity of 2.13×10^4 V/W and detectivity of 2.33×10^9 cmHz^1/2/W.
• Results surpass those of previously reported metal-type and diode-type microbolometers in CMOS.

Conclusions:

• The developed polysilicon microbolometer offers superior performance compared to existing CMOS-based technologies.
• This technology shows significant potential for low-cost, high-performance uncooled microbolometer arrays for infrared imaging.
• The findings pave the way for advanced infrared sensing solutions.