New Frontiers: beyond silicon CMOS

02/01/1997

New frontiers: Beyond silicon CMOS

Predicting the future is risky. Thomas Edison said that alternating current was a waste of time. One micron was supposed to be the limit of optical lithography. The year 1996 was supposed to be another fantastic year for the industry. So when, a few months ago, someone asked me to predict the next "Big Thing," I was reluctant.

Current trends and leading edge research do provide hints, though. As the history of the semiconductor industry shows, increased integration almost always leads to unexpected new applications. When transistors (or vacuum tubes) were expensive, computers belonged exclusively to government and the biggest of big corporations, and they were devoted to Important Problems like census taking and bomb building. Then the integrated circuit came along, leading directly to personal computers, but also to a whole range of silicon-based consumer products, from compact disk players to singing greeting cards. If the tendency to increased integration holds, here are a few educated guesses about the next steps.

Low power electronics are a safe bet, since they`re already emerging in consumer products. This year at COMDEX, IBM demonstrated a system that could transfer business card information with a handshake, with the user`s body serving as the conductor. Researchers at MIT`s Media Lab are experimenting with electronic ink, offering the response time of a computer screen and the resolution of paper. For the long term, such ultra-low power applications as these promise to redefine computing altogether, freeing users from the tyranny of displays and keyboards.

Micromachined sensors and actuators are another safe bet. Micromachined chemical sensors promise to reduce the cost and turnaround time of medical testing, not to mention food and drug quality assurance. Add microactuators, and you get integrated systems that can measure and respond to environmental changes. For example, an air bag could determine the weight of the passenger and whether his seat belt is fastened or not, altering deployment force accordingly; a diabetic might wear an unobtrusive device to monitor blood sugar levels and dispense insulin as needed. If history repeats itself, greater integration will produce a whole range of new applications, from the sublime (microscopic probes for repairing nerves?) to the ridiculous (self-stabilizing anti-slice golf balls?).

Extrapolating current trends a little further, we find optics and electronics merging to create new optoelectronic systems. Conventional optical elements use GaAs, CdTe, and other III-V and II-VI compound semiconductors, requiring processing regimes that are incompatible with silicon circuitry. Luminescent porous silicon, though still confined to research laboratories, suggests that one day optics and electronics will coexist. Optical interconnects would be faster, and escape the crosstalk and RC delay worries that plague conventional wiring. Extrapolating a little further, arrays of optical elements could transform image processing, bringing machine vision closer to human vision.

Technologies other than silicon are on the horizon, too. High temperature ceramic superconductors are starting to emerge from the lab as wireless communications demand low-loss microwave filters. Conducting polymers are being used to make flexible, transparent logic elements for displays. Early research on molecular devices explores the switching properties of individual organic molecules.

Predicting the future is risky. Ten years from now, I expect I`ll look back at this editorial and laugh at my na?ve mistakes. Still, I`ve enjoyed speculating a little bit, and I`d like to hear your ideas about the next big breakthrough. Send me e-mail at the address above, or write to me at Solid State Technology, Ten Tara Blvd., 5th Floor, Nashua, NH 03062.

Observant readers will notice that my title, above, has changed to Chief Technical Editor. This new role will allow me to concentrate on technology coverage. I`ve enjoyed conversing with the industry through this page, and I look forward to continuing the dialogue in my new role.