Terri S. Fiez - US grants

The focus of this research is the development of high performance analog architectures and circuits for mixed analog-digital IC's. Emphasis will be placed on improving the immunity of the analog circuits to digital switching noise and in obtaining high speed and accuracy analog circuit performance with the newly emerging 3.3 Volt power supply standard. Current-mode circuits will be examined as a way of overcoming these limitations and this research will yield a general understanding of the advantages and limitations of current-mode circuits as compared to voltage-mode circuits. The current-mode circuits will be used to implement area efficient, high-order sigma-delta A/D converters.

ABSTRACT EEC-9708324 Ringo The performance of submicron CMOS components like transistors, resistors and capacitors are usually limited by the parasitic substrate elements. Past processing micromachining techniques can be employed to physically remove the cause of some of these parasites. This three-year continuing award will study the development of micromachining techniques to enhance the performance of mixed-signal circuits in a submicron CMOS technology. During the first two years, a set of primitive devices will be developed using an advanced micromachining process to be performed at the Washington Technology Center. The devices will be characterized to determine design rules and device models suitable for mixed-signal circuit simulation. In the second and third year, primitive circuit blocks will be built to determine reliability and characterize the improvement in the circuit operation. Research results will include the design rules and the specification necessary for the two past processing micromachining techniques developed to eliminate parasitic substrate elements.

The goal of this Engineering Microsystems: "XYZ" on a Chip project is to investigate the fabrication of a micro heat engine, which will use commonly available liquid hydrocarbon fuels, to efficiently generate electric power to be used by Micro-Electro-Mechanical Systems (MEMS) and microelectronic devices. This micro heat engine is expected to deliver electric power in the range of milliwatts to watts while supplying voltages from 1 to 30 volts. The research involves the creation of a totally new class of heat engine, which takes advantage of thermophysical phenomena unique to small scales.

The result will be a heat engine that is efficient and that can be mass-produced with techniques developed for microelectronics and MEMS. The proposed engine is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle which approaches the ideal vapor Carnot cycle. Mechanical power is converted into electrical power through the use of a piezoelectric generator. The generator, which takes the form of a flexible membrane, can be readily manufactured using MEMS fabrication techniques but still delivers high conversion efficiency. This approach eliminates the requirement to manufacture complex micromachines such as rotary compressors and turbines, resulting in a very simple but highly efficient device. In addition, since the micro heat engine is an external combustion device, it will have broad fuel flexibility, making it useful in a wide range of applications including military, space, biomedical, and consumer products.