Technology Bulletin

Germanium speeds silicon circuits 2 to 4x

IBM says it's found a way to increase semiconductor speed between two- and four-fold: add germanium to a silicon transistor's base. The germanium builds in an electric field, changing the physics of a device and accelerating electrons across the transistor, explains IBM Fellow Bernard Meyerson. In addition, the SiGe transistors are precisely "grown" layer by layer, instead of firing atoms into silicon, making it possible to boost circuit-design accuracy up to 100-fold. And, because the technology uses mostly conventional silicon, it can be produced in "regular" semiconductor-fabrication facilities, making it dramatically less expensive than specialty materials such as gallium arsenide. Hughes Electronics, which has been working with IBM on the technology, predicts "availability as early as 1997 of the fastest silicon ICs used in communications applications to date," according to Hughes spokesman Ron Finnila. For more information, e-mail grnberg@watson.ibm.com, visit http://www.research.ibm.com/sigetech/.

Calculating weld safety

Pipelines, reactors, agitators, boilers, exhaust systems, and more need to be repaired or replaced because welded joints fail to reach the end of their anticipated fatigue life. The reason: calculation procedures for ductile steel are inadequate because they cannot take into account the complex multi-axial stresses to which welded joints are exposed. Many designers react by using more and stronger welds than necessary to ensure the safety of the finished product. In an attempt to overcome both problems, Professor Cetin Morris Sonsino at the Fraunhofer Institute, Darmstadt, Germany, has developed the calculation method "hypothesis of effective equivalent stress." The method recognizes that it is local shear strains or stresses that are responsible for the failure of critical component sectors. Based on Sonsino's findings, the Institute has developed software that allows designers to use the calculations in their day-to-day work. The project's success should let designers optimize their plans without having to make allowances for undefined safety factors, leading to considerable materials savings. FAX C.M. Sonsino at (+49) 6151 705 214.

Kiddie video camera uses CMOS chip

VISION, a Scottish electronic imaging company, has linked with U.S. toy manufacturer Tyco to develop a video camera just for kids. The Tyco "VideoCam" provides black and white video pictures, which will be relayed directly into a television via a standard VCR player. The technology combines both image sensing and image processing on the same CMOS chip. VISION's CMOS imaging technology has resulted in a lightweight, sturdy, simple to operate, and cost-effective to make video camera. Advantages include reduced cost, size, and power requirements. For details, FAX (408) 374-4722, e-mail info@vvl.co.uk .

ATM switch accelerates data to 5 Gbps

Toshiba Corp. of Japan has developed a prototype switching device for an asynchronous-transfer-mode (ATM) system, a next-generation high-speed data-transmission network, that attains a data exchange speed of 5 gigabits per second (Gbps). This is the fastest rate achieved by a single CMOS chip to date, say company sources. Today, the transmission speed of commercial-level ATM switch ICs ranges from 1 to 2.5 Gbps. The 8-input/8-output (622 Mbps per port) switching IC meets specifications proposed by the ATM Forum, the U.S.-based international consortium of ATM equipment manufacturers. ATM networks use high-speed switching to transmit multiple data types, such as audio signals, image signals, text, and voice. Data flows are broken down into cells made up of 48 bytes of information and 5 bytes of address data. High-speed switching transmits cells individually in a prioritized order. "ATM networks are among the most promising of advanced communication networks. I believe this new switching device will put us in the forefront of ATM innovations," says Kenshi Manabe, technology executive of Toshiba's semiconductor group. For more information, phone (800) 879-4963.

Save images in a crystal

Scientists at Israel's Technion R&D Foundation Ltd. have developed novel techniques for storing and retrieving information in crystal media--and for the application of light patterns and electric fields to crystals. These techniques induce controllable domain structures for data storage. They provide both method and apparatus for fixing images, holograms, and domain gratings by applying an electric field on a crystal and simultaneously illuminating it with a light pattern. The method also provides for reversibly fixing images and holograms in a crystal. The development can overcome the problems that present photo-refractive techniques have encountered, such as the nonpermanency of the light patterns in a crystal, which make them unsuitable for storing data. FAX (972) 4-8320845.

Rechargeable batteries charge research effort

Current battery technology leaves a lot to be desired when it comes to long life and energy output. One new venture addressing these needs has been formed by BC Research Inc., DynaMotive Technologies Corp, and Moli Energy, all of Vancouver, Canada. The R&D venture will develop high-capacity carbons for rechargeable lithium batteries. The partners will characterize material properties, and develop applications for the new carbon forms. Lithium ion batteries have high energy density and good cycle life. The partners anticipate that battery anodes made with the new carbon forms will permit smaller and more powerful batteries with longer times between recharges than current technologies. FAX (604) 222-5545.

Scientists ponder outer-space bubble trouble

Put a pot of water on a hot stove, and you'll soon see steam bubbles scurrying toward the surface. But if you try to boil water aboard an orbiting space shuttle, something else will happen: One huge bubble will form along the heated surface and stay there, refusing to carry heat away. Soon, portions of the heated container will dry out, and it may crack. However, by using sound waves, electric fields, and forced-liquid currents, three scientists at The Johns Hopkins University's Whiting School of Engineering hope to make bubbles behave in more productive ways in the absence of gravity. The research, important because bubbles play a major role in cooling and water purification, will prove crucial as space vessels spend more time in weightless conditions. In normal gravity, gas bubbles are lighter than the surrounding liquid. Thus, they detach and float upward, stirring the liquid, and condensing and transferring some of their heat to the cooler water. In space, however, the bubbles don't rise because they are no longer lighter than the water around them. Mechanical engineers Andrea Prosperetti, Cila Herman, and Hasan N. Oguz will study ways to dislodge the giant bubbles that form during gravity-free boiling. The research is sponsored by a multi-year grant from NASA's Microgravity and Science Applications Div. For details, e-mail prs@jhu.edu , FAX (410) 516-5251.

Novel needle helps characterize tissue

MIT researchers have developed a needle embedded with microchips that could replace several probes doctors currently use to characterize human tissue such as tumors. The needle could also be less expensive than current probes and is 30% smaller in diameter--a fact that patients are sure to appreciate. The researchers, led by Kenneth S. Szajda of the Harvard-MIT Division of Health Sciences and Technology, have built a prototype device that measures temperature. The ultimate goal: a needle that also measures such parameters as pH, oxygen concentration, and radiation dosage. The needle was originally developed for use in the hyperthermic treatment of cancer, where heat is used to improve the effectiveness of radiation and chemotherapy. "Characterization of the tumor environment is essential to planning and evaluating hyperthermic treatments," says Dr. Szajda. Though conventional temperature probes for this purpose "work very well," he said, "they do have limitations. Our idea was to build something that would work even better." For details, e-mail Elizabeth Thomson at thomson@mit.edu .

Polymer could insulate circuits

Researchers at Rensselaer Polytechnic Institute have discovered an effective way to coat surfaces with polynaphthalene, a long-chain polymer that has a very low dielectric constant. As a result, the polymer could find application in insulating high-speed, high-density microelectronic circuits. The problem with using long-chain polymers as insulating materials for multilevel chips has been finding an effective and environmentally safe way to apply them as thin-film coatings. Traditional spin coating relies on using dissolved materials, and some thermally stable long-chain polymers, such as polynaphthalene, do not easily dissolve. At Rensselaer, Toh-Ming Lu and James Moore evaporated ortho-diethynyl-benzene, a monomer precursor, and deposited it on a heated silicon wafer in the university's clean room. The precursor transformed into a very thin transparent coating of polynaphthalene. Tests show the coating to have a dielectric constant of less than 2.6 and to be stable at temperatures of 600C. For details visit http://www.rpi.edu/dept/NewsComm/tips/news_ideas.asp .

Parallel-processor architectures get flexible

Imagine connecting all the computers in a building so that they can share resources, allowing a computer that is running a really big program to borrow memory--and even processors--from idle computers nearby. Now imagine that such a system would be comparable in cost and reliability to a normal network. That is one of the possible results of FLASH--Flexible Architecture for Shared Memory--a project being conducted at Stanford University's Computer Systems Laboratory. Its goal: to develop a new and more flexible type of parallel processor--a computer that uses more than one central processing unit at once. The 46-member-plus research team expects to have a prototype of the machine built and running by the end of the year. It is also working on HIVE--an operating system that would allow the computer to run many existing programs. The project, a cooperative effort with LSI Logic and Silicon Graphics, is supported by the Department of Defense's Advanced Research Projects Agency. For details, e-mail david.salisbury@forsythe.stanford.edu .