Capacitive micromachined ultrasonic transducer (CMUT) chemical sensor and its interface circuits
Abstract/Contents
- Abstract
- Miniaturized chemical sensors based on microelectromechanical-systems (MEMS) offer competitive advantages over existing bench-top chemical analyzers, such as small size, low power consumption, low cost due to batch fabrication, and CMOS compatibility. The potential for system integration of these chemical sensors with on-chip CMOS circuitry expands the spectrum of use, including consumer, industrial, and homeland security applications. This thesis introduces a miniaturized resonant chemical sensor based on a 50-MHz capacitive micromachined ultrasonic transducer (CMUT). With a high mass sensitivity of 4.3 ag/Hz, this CMUT-based chemical sensor achieves excellent volume sensitivity of 21.2 ppt/Hz to dimethyl methylphosphonate (DMMP), a common simulant for Sarin gas. In addition, a direct application of a mesoporous silica thin-film on a CMUT for relative humidity and carbon dioxide detection is presented. Using a mesoporous silica thin-film with a pore size of ~11 nm, this sensor achieves one of the lowest volume resolutions and a sensitive detection of 5.1 × 10-4%RH/Hz to water vapor in nitrogen. In addition, a mesoporous thin-film that is functionalized with an amino-group is directly applied on the resonant sensor, which exhibits a volume sensitivity of 1.6 × 10-4%/Hz and a volume resolution of 1.82 × 10-4% to carbon dioxide in nitrogen. Lastly, this thesis describes the sensor interface circuitry for CMUT and discusses the frequency noise analysis of CMUT-based oscillators. Specifically, a multi-channel interface integrated circuit (IC) implemented using 0.18-um CMOS technology, which results in reduced area and power consumption for each channel is presented. Two-channel detection of relative humidity is demonstrated using this circuit.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Lee, Hyunjoo Jenny |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Howe, Roger Thomas |
| Primary advisor | Khuri-Yakub, Butrus T, 1948- |
| Thesis advisor | Howe, Roger Thomas |
| Thesis advisor | Khuri-Yakub, Butrus T, 1948- |
| Thesis advisor | Bahai, Ahmad R. S |
| Thesis advisor | Murmann, Boris |
| Advisor | Bahai, Ahmad R. S |
| Advisor | Murmann, Boris |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Hyunjoo Jenny Lee. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Hyunjoo Jenny Lee
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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