Ballistic Nanotransistor From Lucent's Bell Labs May Lead to Smaller and Faster Silicon Chips.WASHINGTON--(BUSINESS WIRE)--Dec. 6, 1999-- Researchers at Lucent Technologies' Bell Labs have developed a method to significantly improve the flow of current in nanoscale At nanometer size. Any device only a few nanometers in size is nanoscale. See nanotechnology and nanometer. transistors -- a characteristic that may help the semiconductor industry continue making smaller and faster silicon chips. Dubbed dub 1 tr.v. dubbed, dub·bing, dubs 1. To tap lightly on the shoulder by way of conferring knighthood. 2. To honor with a new title or description. 3. a "ballistic nanotransistor" for its virtually unimpeded unimpeded Adjective not stopped or disrupted by anything Adj. 1. unimpeded - not slowed or prevented; "a time of unimpeded growth"; "an unimpeded sweep of meadows and hills afforded a peaceful setting" flow of current -- similar to a bullet whizzing through the air -- the device is roughly four times smaller than today's transistors. In recent years, the Years, The the seven decades of Eleanor Pargiter’s life. [Br. Lit.: Benét, 1109] See : Time semiconductor industry has increased the performance of chips by decreasing the size of their transistors, which increases their switching speed. However, one component of a transistor - its insulating layer - will limit the continued shrinkage because a short circuit will occur when it becomes too thin; the insulating layer lies between the transistor's gate, which turns the current on and off, and the channel, through which current flows. To overcome the limitations posed by the insulating layer, the Bell Labs researchers decided to tackle another major factor that limits a transistor's speed: the resistance encountered by current as it flows through the channel. In today's silicon-based transistors, only 35 percent of the input current flows, via the channel, from a transistor's "source" to its "drain;" the remainder scatters as it collides with the rough edges of the insulating layer. "The electrons going through the channel are like a ball going through a pinball game," said Bell Labs researcher Greg Timp Gregory Timp is a professor of electrical engineering at the University of Illinois at Urbana-Champaign. Gregory Timp received his Ph.D. in Electrical Engineering from the Massachusetts Institute of Technology in 1984 under the direction of Mildred Dresselhaus. , who presented his research findings today at the International Electron Devices Meeting The International Electron Devices Meeting is an annual conference held alternatively in San Francisco, California and Washington D.C. Established in 1954, IEDM is the world's main forum on advancement in semiconductor and electronic devices. . "In our device, we not only made the channel very short to minimize the channel resistance, but we also removed nearly all the `pinball bumpers' by making the insulating layer smoother than it is in conventional transistors. This results in 85 percent of the current being transmitted from the source to the drain, which yields the ballistic transport In solid state physics, the term ballistic transport refers to the transport of electrons in a medium where the electrical resistivity due to the scattering, by the atoms, molecules or impurities in the medium itself, is negligible or absent. ." Although other researchers have attained ballistic effects in nanotransistors, they needed to cool their devices to nearly minus 200 degrees Centigrade centigrade /cen·ti·grade/ (sen´ti-grad) having 100 gradations (steps or degrees); see under scale. cen·ti·grade adj. Celsius. to reduce the scattering, or they used exotic materials. "This is the first ballistic nanotransistor that operates at room temperature with conventional silicon technology," Timp said. The Bell Labs nanotransistor has a 40-nanometer gate, which is roughly 2,000 times smaller than the width of a human hair, and its channel length is 25 nanometers. There were several key elements involved in making a ballistic nanotransistor. Timp and his colleagues used an unconventional process, known as rapid thermal oxidation In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer (semiconductor). The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. , to "grow" the insulating layer, or gate oxide, on the silicon wafer. This process adds oxygen to silicon at 1,000 degrees Centigrade for 10 seconds. "This results in a smooth interface between the silicon wafer and the gate oxide," Timp said. When Timp and his colleagues tested the new devices, they were surprised by a counterintuitive coun·ter·in·tu·i·tive adj. Contrary to what intuition or common sense would indicate: "Scientists made clear what may at first seem counterintuitive, that the capacity to be pleasant toward a fellow creature is ... finding, which may have implications for the semiconductor industry. At first, the researchers tested nanotransistors with gate oxides that were only 1.3 nanometers thick, compared with today's average of 2.8 nanometers. The drive current efficiency was about 75 percent. However, when the researchers performed a computer simulation of a slightly thicker gate oxide -- 1.6-nanometers -- they predicted an 85 percent efficiency, which appeared odd because thicker gate oxides typically hinder current flow. Experimental results confirmed the prediction, which may ease the industry's need for making thinner gate oxide layers. "It appears that electrons travel better when the gate oxide is slightly thicker because the electrons are not as attracted to the gate, which is directly above the gate oxide layer," Timp said. Lucent Technologies, headquartered in Murray Hill Murray Hill may refer to one of the following places:
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