Physical Sensors & Devices

This project aims to develop a fully integrated micromechanical clock oscillator which outperforms current quartz-based clock oscillators in terms of both size and cost. A 32-kHz micromechanical resonator with a temperature coefficient better than 10 ppm over the commercial temperature range will act as the oscillator's reference. In addition, this oscillator will utilize an integrated fabrication process above modern transistor circuits in order to minimize device footprint and production expense.

Project end date: 08/25/15

Two dimensional electron gas (2DEG) and hole gas (2DHG) can be induced at the interface of epitaxial AlGaN/GaN due to spontaneous and piezoelectric polarization. Such electronic system features high transport mobility, carrier density and piezoelectric sensitivity. Mechanical strain and vibrations of devices can be transduced to electronic signals in embeded 2DEG for further processing. In this project, we study physical properties of this strongly-coupled electromechanical system, and develop possible devices such as pressure sensor, MEMS resonator, ultrasonic transducer, etc....

We are designing a conductometric soot sensor that measures the change in conductance resulting from soot deposition onto the sensor. Although previous work has been done on conductometric soot sensing, current sensors are power intensive (5-30 W) and slow (60-170 s between sensing cycles) due to their large size, ineffective thermal insulation, and the high currents required for soot combustion (when self-regenerating). We propose to use MEMS fabrication methods to develop a miniaturized conductometric soot sensor with a built-in polysilicon microheater for self-regeneration, whose...

Despite their small size, low power dissipation, and low cost, the large bias and scale factor errors of current MEMS inertial sensors preclude using them for dead reckoning navigation. Although these shortcomings can be overcome with precision manufacturing and extensive calibration, such solutions suffer from high cost and secondary effects such as long term drift. Presently, the use of in-situ calibration techniques in MEMS sensors is limited to the electronic interfaces, where they are instrumental for reducing drift arising from electronic components. This project extends the...