Research Overview

Materials, Processing, and Devices for Microelectronics and Macroelectronics. The continual scaling of VLSI devices to smaller dimensions, higher performance, and higher integration levels over the last thirty years has directly enabled the "information society." Scaling has reduced the cost of intelligence (that is, electronic circuits) by some six orders of magnitude, while performance has continuously increased. Continued growth of the information economy depends on the further scaling of silicon-based electronic devices to the 0.1 micron (nanoscale) level and beyond. Our group works to achieve this goal through the science and technology of silicon-based heterojunctions and three-dimensional integration for VLSI. The work involves the growth of novel materials on a near-atomic scale, materials processing, and finally their application into electronic devices such as heterojunction transistors, FET's, quantum devices, and also optoelectronic devices such as infrared detectors and emitters. Specific focuses in our lab include rapid thermal chemical vapor deposition, silicon-germanium and silicon-germanium-carbon alloys, silicon-on-insulator, and heterojunction devices.

On the other extreme, many electronic information processing systems as a whole are limited on both a fundamental and practical economic level by the human-machine interface. For example, the ability to deliver high-quality video is often limited by the display. In this area it is generally desirable to make products big (for example, the display), as opposed to making them small, as in traditional microelectronics; hence the label "macroelectronics" has emerged. Because low cost over a large area is a requirement for widespread impact in the future in this field, materials and technologies very different from VLSI are necessary. For example, polycrystalline and amorphous materials, instead of single crystals, and low-cost alternatives to conventional photolithography and etching are highly desirable. To this end, our lab focuses on organic and polymeric semiconductors because of their ease of deposition over large areas (and applications to organic LED's and FET's) as well as on amorphous and polycrystalline silicon for TFT's. Coupled with these materials are efforts to pattern them and fabricate devices using large-area printing technologies such as ink-jet printing, as well as work to fabricate systems such as flat panel displays on unconventional flexible and lightweight substrates.

These projects both encompass a wide range of activities ranging from basic materials science and physics to electrical engineering and industrial collaboration, and benefit extensively from the interdisciplinary nature of the Center for Photonic and Optoelectronic Materials (POEM) at Princeton and the Princeton Materials Institute (PMI).