| AVS 61st International Symposium & Exhibition | |
| MEMS and NEMS | Thursday Sessions |
| Session MN-ThP |
| Session: | MEMS and NEMS Posters |
| Presenter: | Po-Kai Huang, National Taiwan University, Taiwan, Republic of China |
| Authors: | P.-K. Huang, National Taiwan University, Taiwan, Republic of China C.-Y. Kuo, National Taiwan University, Taiwan, Republic of China P.-H. Kuo, National Taiwan University, Taiwan, Republic of China T.-H. Tzeng, National Taiwan University, Taiwan, Republic of China S.-S. Lu, National Taiwan University, Taiwan, Republic of China W.-C. Tian, National Taiwan University, Taiwan, Republic of China |
| Correspondent: | Click to Email |
The detection limit for the gas sensor has been an important factor for the low concentration compound measurement, especially for the detection of disease biomarkers from exhaled human breath air. In this study, we developed a CMOS-based volatile organic compounds (VOCs) sensor with either by a system on chip (SOC)-enabled negative feedback calibration (NFC) readout circuit or a custom-made voltage divider.
The sensor and the SOC-enabled NFC chip were both fabricated by the commercial TSMC 0.35μm two poly Si and four metal (2P4M) layer process. The sensing module included a stacked of interdigitated electrodes (IDEs) with polysilicon microheater and the sensing material of monolayer protected gold nanoclusters (MPCs) coated on the electrodes.
In order to conquer the sensor resistance variation created by the MPCs spraying process, the NFC readout circuit was used to overcome the resistance value fluctuation of the VOCs sensor. The sensitivity of our sensing module, consisting of the CMOS-based sensor and the SOC-enabled NFC readout circuit, was increased by approximately two times compared to the previous design. With our sensing module, a wide dynamic range of toluene detection from 30 ppm to 6000 ppm was demonstrated. The sensor responded rapidly, with the rising time and the recovery time both less than six seconds.
With this VOCs sensing module, the detection of lung disease biomarkers from exhaled human breath air could be achieved. Ultimately, the VOCs sensor and NFC readout circuit will be integrated on the same chip to further miniaturize the systems and to minimize the noises in the future.