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Silicon Carbide Smokes from Sandpaper to Stadium Displays
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Materials
Silicon Carbide Smokes from Sandpaper to Stadium Displays
What's harder than nails, pretty as diamond, and hotter than red hot chili peppers? Silicon carbide. If you haven't heard about it yet, don't feel badly. Silicon carbide crystals and semiconductor wafers are an emerging technology developed by Cree Research, a small Durham, N.C., company. Back in 1991, Cree received almost $2 million in co-funding from the National Institute of Standards and Technology's Advanced Technology Program for a two-year project to develop a better way to process silicon carbide into large, high-quality single crystals. Today, the company has growing revenues for a wide range of silicon-carbide-based products and for the sale of raw silicon carbide wafers to the electronics industry.
Commonly used as grit on sandpaper, silicon carbide is almost as hard as diamond, tolerates high temperatures, and responds to electrical currents by emitting blue light. However, it's difficult to grow enough high-quality silicon carbide crystals at large enough sizes to make the material economically viable.
Cree's ATP funding helped the company double wafer sizes from about 2.5 to 5 centimeters, reduce defects from 400 to 180 per square centimeter and reduce costs for blue LEDs (light emitting diodes) from 48 cents to 18 cents. Cree's lightweight blue LEDs now are used in a wide range of products from auto dashboards to giant stadium instant replay displays.
Media Contact:
Michael Baum, (301) 975-2763
The Art of Science
NIST Image Gallery Offers Colorful View of Microscopic World
Scientific progress marches forward in complex mathematical equations and technical language that are often indecipherable to non-scientists. However, science has another side that can engage the least scientifically savvy among us. Scientists regularly produce colorful, even beautiful, images in lab experiments probing the microscopic world.
The National Institute of Standards and Technology offers a look at some of these images on its World Wide Web site. Visit the Image Gallery at Internet address http://www.nist.gov/public_affairs/gallery/gallery.htm or just click on the photo collage at the top of the NIST home page (http://www.nist.gov). The Image Gallery contains graphics from NIST laboratory research as well as graphics from projects conducted under NIST's Advanced Technology Program. Also included are pictures of scientists working with laboratory equipment, pictures showing winners of the Malcolm Baldrige National Quality Award, images from the Manufacturing Extension Partnership, and photos of NIST sites and buildings in Gaithersburg, Md., and Boulder, Colo.
Surfing through the Image Gallery allows you to find captions and articles describing the images and corresponding research projects, along with links to web pages providing more information about specific research areas.
Media Contact:
Linda Joy, (301) 975-4403
Manufacturing
Future Factories May Use 'Plug and Play' Systems
An emerging technology that enables better communication between software and machinery may alleviate some of the recent strain caused by a shift in the way the U.S. electronics manufacturing industry does business. That shift, seen most dramatically over the past five or so years, has placed greater burdens on subcontractors. Companies that ordinarily would assemble circuit boards are now expected to perform many additional services, including design work and costly research and development.
Consequently, those companies are handling a greater diversity of manufacturing jobs in their factories, often making different products from one shift to another. What the companies really need is an advanced, so-called "plug-and-play" system that will enable them to rapidly adjust their hardware and software to accommodate the manufacture of their rapidly changing product lines.
Scientists at the National Institute of Standards and Technology are among other researchers working on the Plug and Play Factory project, which is being developed by the National Electronics Manufacturing Initiative, a consortium of industry, universities and government agencies addressing the most pressing needs for U.S. electronics manufacturers. The Plug and Play Factory was demonstrated on Oct. 28, 1998, during the Electronics Assembly Expo hosted by the Institute for Interconnecting and Packaging Electronics Circuits and Surface Mount Technology Association, in Providence, R.I. A prototype has been built at the Georgia Institute of Technology.
Media Contact:
Emil Venere, (301) 975-5745
Microchips
Technique May Help Industry Make Even Smaller Transistors
Semiconductor manufacturers now are able to make circuit features, such as transistor connections, whose widths are actually too small to be measured reliably with existing tools. Without reliable measurements, manufacturers will not be able to properly control the quality of integrated circuits coming off a production line. In order to test the accuracy of microscopes used to measure features--such as the lines in microchip circuitry--manufacturing engineers must have reference features with known dimensions at least as small as the lines being manufactured. Because their dimensions are known, those reference lines then can be used to test the performance of microscopes that are essential to controlling the precision of circuits being produced. If the microscopes get out of adjustment, they then can be calibrated back to the correct settings.
But scientists have been unable to make precisely measured reference lines as narrow as the lines that microchip manufacturers can make. Now, scientists at the National Institute of Standards and Technology and Sandia National Laboratories are coming up with a way to make extremely narrow lines out of silicon, which can be etched with precisely flat surfaces and known, rectangular cross sections. Scientists expect to eventually use the technique to test microscopes designed to allow accurate measurement of circuit features as small as one-tenth of a micrometer (or 500 times thinner than a human hair). That's five times smaller than the circuit features in current microchips.
Media Contact:
Emil Venere, (301) 975-5745
Moisture Detection
New Instruments to Help Prevent Soggy 'Chips'
Bikes and bellbottoms. Ice cream and ketchup. Water and microchips. Some things just don't go together. But keeping water--all water--out of semiconductor processing is darn difficult. Very small amounts of water vapor in a processing gas used in semiconductor fabrication can lower yields and limit microchip performance. To help manufacturers keep better tabs on water vapor, researchers at the National Institute of Standards and Technology recently developed a new instrument that can produce gases with less than three parts per billion of water vapor, about 1,000 times dryer than was previously possible at NIST.
The new system passes a "carrier gas" over pure ice maintained within tightly controlled temperature and pressure ranges. This approach was used to test a high sensitivity laser-based hygrometer designed and built for commercial use by Southwest Sciences Inc. of Santa Fe, N.M. The hygrometer sends an infrared beam of light through the humidified gas. Improved detectors sense how much light is absorbed, which is directly related to the concentration of water vapor in the gas. Testing this prototype with the aid of the new NIST instrument proved to be critical to development of this improved moisture sensor. Using the new system, NIST plans to begin offering calibration services for trace-level hygrometers and humidity generators in early 1999.
Media Contact:
Linda Joy, (301) 975-4403
Small Business
CDI Seals Up Profits with MEP Center's Help
CDI Seals Inc., of Humble, Texas, makes seals--rubber seals, plastic seals, seals with mesh, seals for drilling, hydraulics and chemical processing. CDI wanted to make their thousands of products better and more efficiently. The company turned to the Texas Manufacturing Assistance Center, a local affiliate of the nationwide Manufacturing Extension Partnership, a program of the National Institute of Standards and Technology.
TMAC's engineers visited CDI; talked to management and staff; surveyed CDI's production, assembly and shipping operations; and soon produced a list of areas to improve. Recommended improvements included training operators on how variables in the extrusion process affect quality, better cleaning of equipment to reduce scrap-causing contamination and documenting trimming methods. "We've already addressed many of them," said CDI President Bill Heathcott. "We'll continue to make day-to-day incremental improvements. I consider TMAC a real good investment," said Heathcott. For information about CDI Seals or TMAC, call TMAC's Houston office at (713) 752-8440.
With a nationwide network of more than 2,000 manufacturing experts, the Manufacturing Extension Partnership is helping small and mid-sized manufacturers improve productivity, increase profits and enhance competitiveness. Smaller manufacturers can call (800) MEP-4MFG (800 637-4634) to reach the nearest center or visit http://www.mep.nist.gov on the World Wide Web.
Media Contact:
Jan Kosko, (301) 975-2767
Tech Trivia
In 1957 computer specialists at the National Bureau of Standards (now NIST) connected the first picture scanner to the Standards Electronic Automatic Computer, the first electronic computer with an internally stored program in the U.S. government.
In constructing the first image scanner for computers, National Bureau of Standards (now NIST) scientists made several decisions, many of which survive in image processing today. An admittedly bad one was the selection of the square binary pixel which lowers image quality compared to what was done in ancient mosaics using many shapes and many colors.
The image-processing field pioneered at the National Bureau of Standards (now NIST) has spawned research in various kinds of vision systems. These include vision systems that robots could use in navigating the world.
U.S. Department of
Commerce
Technology Administration
National Institute of Standards and Technology
Editor: Linda Joy
HTML conversion: Crissy Wines
Last update: October 27, 1998
(to NIST News Page)
