Journal article
High quantum efficiency annular backside silicon photodiodes for reflectance pulse oximetry in wearable wireless body sensors
Department of Micro- and Nanotechnology, Technical University of Denmark1
Silicon Microtechnology Group, MicroElectroMechanical Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark2
MicroElectroMechanical Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark3
The development of annular photodiodes for use in a reflectance pulse oximetry sensor is presented. Wearable and wireless body sensor systems for long-term monitoring require sensors that minimize power consumption. We have fabricated large area 2D ring-shaped silicon photodiodes optimized for minimizing the optical power needed in reflectance pulse oximetry.
To simplify packaging, backside photodiodes are made which are compatible with assembly using surface mounting technology without pre-packaging. Quantum efficiencies up to 95% and area-specific noise equivalent powers down to 30 fW Hz(-1/2) cm(-1) are achieved. The photodiodes are incorporated into a wireless pulse oximetry sensor system embedded in an adhesive patch presented elsewhere as 'The Electronic Patch'.
The annular photodiodes are fabricated using two masked diffusions of first boron and subsequently phosphor. The surface is passivated with a layer of silicon nitride also serving as an optical filter. As the final process, after metallization, a hole in the center of the photodiode is etched using deep reactive ion etch.
Language: | English |
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Year: | 2010 |
Pages: | 075020 |
ISSN: | 13616439 and 09601317 |
Types: | Journal article |
DOI: | 10.1088/0960-1317/20/7/075020 |
ORCIDs: | Hansen, Ole , Birkelund, Karen and Thomsen, Erik Vilain |