Thin Films by Chemical Vapor Deposition

How to build a better semiconductor? This question has been the heart and soul of progress in the electronics industry for the last 40 years. If necessity is the mother of invention, necessity in this case is the appetite for faster and faster computing. A potential solution that has gained favor in the 80s and 90s is to turn away from silicon, the material of choice in microelectronics for decades, toward other semiconducting materials, in particular gallium arsenide.

Because of its inherent properties -- sensitivity to very low currents and light and, especially, the ability to conduct current six times faster than silicon -- gallium arsenide has long been recognized as a rival to silicon's dominance. Nevertheless, while this material is now used in a few specialized applications, such as visual displays and detectors in satellite-receiver dishes, it has barely begun to realize its potential to displace silicon "chips" in computers.

The main obstacle is manufacturing technology. What is needed is the ability to create, on a commercial scale, crystalline "thin films" -- layers of pure, defect-free material only several atoms in thickness. This is where research by T. J. Mountziaris and his colleagues enters the picture. Mountziaris, a chemical engineer at SUNY Buffalo, uses the CRAY C90 at Pittsburgh Supercomputing Center to help understand the intricacies of chemical vapor deposition (CVD), a process for creating thin solid films by starting with material in the gas phase. Though it has advantages over other methods, using CVD to create thin films of compound semiconductors such as gallium arsenide has been limited for the most part to laboratory-scale demonstration projects. "Designing big CVD reactors for mass production," says Mountziaris, "is a very serious problem."We need to understand the fundamentals of the process, especially the chemistry, in order to scale up the reactors."

In recent work, Mountziaris' research group designed a new reactor for studying the chemistry involved in CVD for compound semiconductors. Using this reactor along with supercomputer modeling, they are arriving at new understanding of these complex reactions.

Researcher: T.J. Mountziaris, State University of New York at Buffalo.
Hardware: CRAY Y-MP C90
Software: User developed code
Keywords: chemistry, engineering, chemical kinetics, Chemical Vapor Deposition, CVD reactor, counterflow jet reactor, stagnation flow pattern, reaction zone, gallium arsenide, arsine, silicon, semiconductor, surface reaction, flow rate, thin film, gas.

Related Material on the Web:
SUNY Buffalo, Chemical Engineering Faculty Home Page
Dr. Mountziaris' Home Page
Projects in Scientific Computing, PSC's annual research report.

References, Acknowledgements & Credits