Using an SU-8 photoresist structure and cytochrome C thin film sensing material for a microbolometer

• Published in: Sensors (Basel, Switzerland) Vol. 12; no. 12; pp. 16390 - 16403
• Main Authors: Lai, Jian-Lun, Liao, Chien-Jen, Su, Guo-Dung John
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-11-2012; Molecular Diversity Preservation International (MDPI)
• Subjects: Chemical vapor deposition; Conductivity; Cooling; Cytochrome; cytochrome c; Cytochromes; Cytochromes c - chemistry; Detection; Epoxy Compounds - chemistry; exposure dose method; Heat conductivity; Infrared radiation; Infrared Rays; Insulation; microbolometer; Microorganisms; Photoresists; Platforms; Polymers - chemistry; Process controls; Proteins; Semiconductors; Sensors; Silica; Silicon nitride; SU-8; Surface Properties; temperature coefficient of resistance (TCR); Thermal conductivity; Thin films
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s121216390

There are two critical parameters for microbolometers: the temperature coefficient of resistance (TCR) of the sensing material, and the thermal conductance of the insulation structure. Cytochrome c protein, having a high TCR, is a good candidate for infrared detection. We can use SU-8 photoresist for the thermal insulation structure, given its low thermal conductance. In this study, we designed a platform structure based on a SU-8 photoresist. We fabricated an infrared sensing pixel and recorded a high TCR for this new structure. The SU-8 photoresist insulation structure was fabricated using the exposure dose method. We experimentally demonstrated high values of TCR from 22%/K to 25.7%/K, and the measured noise was 1.2 × 10(-8) V2/Hz at 60 Hz. When the bias current was 2 μA, the calculated voltage responsivity was 1.16 × 10(5) V/W. This study presents a new kind of microbolometer based on cytochrome c protein on top of an SU-8 photoresist platform that does not require expensive vacuum deposition equipment.