Osburn looks to replace Silicon Dioxide insulators with high dielectic constant insulators

August 04, 2005

Chip industry looks to new materials, biology for future

July 22, 2005
Triangle Business Journal

By Heather McGowan
Copyright 2005

DURHAM - Semiconductor research is moving away from merely shrinking chips to creating chips that are chemical or biological in nature.

"One family of research is trying to extend the Moore's Law paradigm," says Frank Pita, director of corporate legal affairs and intellectual property counsel at Semiconductor Research Corp. in Durham. Moore's Law has allowed the price of computing power to fall in half every 18 months, he says. "The way the industry has done this is by shrinking the size of a circuit on a chip in half every 18 months."

But shrinking the size of chips cannot continue into infinity.

"The most promising area with respect to the future would be looking at what's beyond Moore's Law," says Pita. "We are looking at how we are going to be able to process and compute information with something that's probably chemical or biological in nature, or something hybrid in computer chips that's partly chemical and partly biological."

"One of the things we are doing, too, is a new technology called self assembly," he says. The human body constantly recreates cells and renews tissues when a cell dies, so the body is constantly regenerating and reassembling itself," he says. "More people in the chip-making community are looking at how biology (might) permit us to be able to do that. They also are trying to make computer circuits that make themselves."

The chip-making industry also has spent several million dollars a year researching environmentally friendly ways in which to manufacture integrated circuits, says Pita. "We have done our research and have enabled some technologies that allow the recycling of the water and chemicals (in chip-making plants)."

"That waste water is a combination of water and chemicals in it ... Recycling systems. ... will separate the water and the chemicals," says Pita. "Once you pull a certain amount of water up from the environment, you use that water over and over again and never expel anything into the environment. Not only does this help the environment, but the companies are still able to make chips productively and found that they were saving a lot of money on water usage," he adds.

Many researchers, some of whom are located in the Triangle, are investigating alternative materials and other technologies that have the potential to replace the traditional materials used to make semiconductors.

"The idea is to replace the conventional silicon-dioxide based insulator with an insulator having a high dielectric constant," says Carlton Osburn, an electrical and computer engineer at North Carolina State University.

Such insulators can be made thicker while maintaining the same functionality, says Osburn. There is then more opportunity for making the insulating layer thinner, so the device can carry more current, which leads to more operations per second.

"We've been looking at both insulators, plus gate-electrode materials," says Osburn.

"Even further out in time, some researchers are looking at much more radical solutions - different materials and different approaches - because we just don't know where we'll be 15 years from now," he says. "(Some researchers) are looking at different semiconductor materials, materials that possibly could give higher currents, like carbon nano tubes and things like functional molecules that could do different things like provide memory."

Semiconductor Research Corp. recently awarded Osburn a $1.5 million research contract to examine nanoelectronic semiconductor devices. "Our particular center involves a ... big collaboration with participants from nine universities."

In conjunction with SRC, Sematech, another industry consortium headquartered in Austin, Texas, is sponsoring the project to reduce the thickness of gate insulators in electronic devices to promote the development of semiconductors with even more densely-packed transistors.

"That has been the main focus of our center," says Osburn. "We need to keep scaling the insulator thickness to advance devices in the semiconductor industry."

SRC has given Sule Ozev, an electrical and computer engineer at Duke University, two awards: The first award, totaling $218,000, she received in January 2004. The second award, totaling $195,000, she received in October 2004. Both were awarded as three-year research contracts.

Ozev tests radio frequency and analog circuits with test automation and diagnosis techniques. Deviations and defects sometimes occur in the chip manufacturing process, she says. "We are looking for ways to subject the chips to a few test conditions that can guarantee with confidence that the passed chips will function as intended once they are integrated into electronic devices."

SRC recently has awarded Hisham Massoud, an electrical and computer engineering professor with the Pratt School of Engineering at Duke University, a research contract in integrated circuit design and manufacturing that amounts to about $375,000, he says.

Massoud's research focuses on the problems arising from the continuous reduction in the scale of semiconductor devices. He also studies the materials that make up semiconductor devices, as they begin to function differently at smaller scales. As the scales of these devices shrink, transistor density within the device increases, which leads to higher temperatures, he says.

"The trend is, if you operate devices at higher speeds, you start to consume and generate more power. First generation laptops barely warmed your lap. Now if you lay (one) on your lap, you will burn it," he says.

Gate leakage in MOS devices is yet another area that Massoud works with to ensure their levels of performance are still intact. "It will be the wall against which you're going to stop your progress, because beyond that, you cannot afford the heat that is generated," he says.

The interest in semiconductors has begun shifting over to the medical industry.

This cross-pollination has triggered Joseph DeSimone, professor of chemistry and chemical engineering at North Carolina State University and professor of chemistry at the University of North Carolina at Chapel Hill, to conduct research into nanotechnology. DeSimone has applied for research awards from SRC for the new Triangle National Lithography center (TNLC). The center, located in the clean rooms at NCSU, is jointly funded by UNC-CH and NCSU. It uses a 193-nanometer scanner for photolithography that cost the center $12 million.

"The Triangle now has the best capabilities in the nation for making nanoscale structures using photolithography," DeSimone says.