Cmos Microsystem for Portable Environmental Gas Monitoring Applications
DescriptionGas pollutants are known to threaten human health and safety, causing discomfort, illness, and even death, particularly among susceptible individuals such as infants and the elderly, as well as those with respiratory or cardiovascular problems. To avoid such threats, there is a growing need for portable, low cost, low power, gas monitoring systems suitable for continuously examining the surrounding environment. An integrated gas sensor that combines advanced sensor devices and analog front-end readout circuits in a single microelectronics chip package is a desirable solution because of their high potential for precise, power efficient, and compact implementation, rendering them suitable for portable applications.A variety of integrated gas sensors have been reported in the last decade including cantilever, thermoelectric, acoustic resonating, bioluminescent, and polymer-based chemical gas sensor. However, several drawbacks are inherent with these existing sensor technologies, for example, the requirement of heating to a high operating temperature, an external light source (thus is not a fully monolithic approach), instability, and high production complexity. Metal oxide based gas sensors has a great potential to circumvent the above problems, are generally sensitive, and are the most compatible with complementary metal-oxide-semiconductor (CMOS) circuits (e.g. in terms of voltage requirements and fabrication process).In this project, we propose to design, fabricate, and experimentally verify an integrated gas sensing microsystem. The microsystem will consists of a nanostructured metal-oxide chemiresistor gas sensor array and a multi-channel CMOS sensor interface readout circuits. The PI has extensively research sensory microsystems in the past both in metal-oxide gas sensors [1-10], CMOS sensor interface circuits [11-15], and microsystem integration [16-18], which substantially improves the chance of project success.There are three major areas for innovation: (1) High-sensitivity gas sensor array doped optimally (building on a technique that the PI recently devised). Metal-doped nanorods enable room temperature operation, eliminating the energy associated with heating. (2) Strategic combination of CMOS precision analog circuit techniques including baseline cancellation, chopper stabilization, deep weak inversion biasing, and continue-time delta-sigma analog-to-digital conversion to demonstrate state-of-the-art readout signal processing performance. (3) Substantial investigation in both the device and circuit levels, enabling the possibility of cross-level co-design.The proposed technology will enable gas sensing instrumentation that are accurate, low-power, and small-sized. This advance will create opportunities to realize cost-effective, reliable means for environmental monitoring applications, directly addressing pressing challenges faced by both Hong Kong and urbanized areas worldwide.
|Effective start/end date||1/11/19 → …|