Enhanced performances of CMOS-MEMS thermopile infrared detectors using novel thin film stacks
Abstract
This paper presents the design, fabrication and experimental results of two CMOS-compatible micromachined thermopile infrared (IR) detectors. A preliminary interferometric absorber structure and modified interferometric absorber structure with Ge anti-reflection layer is used to enhance the absorptance, respectively. The reference thermopile IR detector only consisting of thermocouple embedded structure is provided with a characteristic interferometric absorber structure composed of passivation layers (Si3N4 and SiO2) and Al/N-polysilicon thermocouples. Compared to the reference thermopile IR detector, the thermopile IR detector modified by anti-reflection layer (Ge) has a higher IR absorptance and increased temperature difference between the hot and cold junctions. The responsivity and specific detectivity of the reference thermopile IR detector are ~256.6 V W-1 and 1.47 × 108 cm Hz1/2 W-1, while those of the modified detector after applying the anti-reflection layer arrive at ~302.3 V W-1 and 1.73 × 108 cm Hz1/2 W-1, which increase by ~18%.
- Publication:
-
Infrared Physics and Technology
- Pub Date:
- November 2019
- DOI:
- 10.1016/j.infrared.2019.103058
- Bibcode:
- 2019InPhT.10203058H
- Keywords:
-
- CMOS;
- Infrared sensor;
- MEMS;
- Thermoelectric;
- Seebeck effect;
- Thermopile