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MAKING MATERIALS Combinatorial methods net a thin-film dielectric discovery
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sing combinatorial methods, scien- alysts and phosphors (C&EN, Dec. 8, tists have discovered a new thin- 1997, page 24; Feb. 9, page 21), includfilm dielectric material, demon- ing a new blue phosphor reported last strating yet another potential application week by the team of University of Califor this rapidly blossoming field. fornia, Berkeley, chemistry professor PeThe insulating material holds promise ter G. Schultz; Lawrence Berkeley Nafor use in integrated circuit technology, tional Laboratory physicist Xiao-Dong say physicist R. Bruce van Dover and col- Xiang; and colleagues [Science, 279, leagues at Lucent Technologies' Bell Labs 1712 (1998)]. in Murray Hill, N.J. Now, electronic materials are joining "It's another nice example of what you the ranks. On the heels of the Bell Labs can do with this combinatorial approach," paper, the Berkeley group will soon be says Eric W. McFarland, director of materi- publishing its own discovery of a barium als characterization and analysis at Symyx strontium titanate system for use in miTechnologies in Santa Clara, Calif., one of crowave devices, Xiang says. the leading developers of combinatorial The Bell Labs method bears some retechnology for materials discovery. There's a need to develop new materials for electronic devices, which are rapidly becoming smaller and smaller: As they shrink in size, some of their electrical properties, such as capacitance, also change. The Bell Labs group has been interested in developing a thin-film insulator that has a dielectric constant greater than Van Dover (right), with coworkers Lynn F Schneemeyer that of silicon dioxide— (left) and Robert M. Fleming, holds wafer on which the material typically used dielectric materials were made. in integrated circuits. To start, they chose combinations of ele- semblance to the combinatorial methods ments—such as zirconium, tin, and tita- already described by Symyx and LBL nium—likely to have this property. researchers, who deposit different They then created more than 30 differ- amounts of substances into discrete arent combinatorial-type libraries of 4,000 rays. The whole substrate is then heated so the different components can comsamples each. The optimal mixture, with a composi- bine or react. But dielectric films must be manufaction of about 2r0_15Sn0_3Ti0_55O2, was at least as good as other silicon dioxide sub- tured at low temperatures, so the Bell stitutes being considered in industry, van Labs researchers deposit the elements simultaneously with sputter guns, producDover says [Nature, 392, 162 (1998)]. "It's a very nice thing that they've ing an intimate mixture without heating. done," says Francis J. DiSalvo, chemistry The materials are applied in a continuous professor at Cornell University and a ma- spread across the substrate, and they are then tested at small, relatively homogeterials development expert. The combinatorial approach, tradi- neous spots. The technique has several advantages tionally associated with drug discovery, has made headlines recently as a possible for materials research. "It combines the powerful new way to accelerate the de- elements simultaneously," explains van velopment of new materials. Publicity Dover, "makes many combinations with has centered on the development of cat- fine variations, and uses fully automated
methods to rapidly characterize the materials' properties." The Bell Labs group says the practical development of their new material still requires work, but that so far, things look promising. "We're really excited," van Dover says. "We came up with this approach, and lo and behold, it worked." Elizabeth Wilson
China's chemical industry ministry is terminated In an effort to improve the efficiency of its chemical industry, China has decided to dissolve its Ministry of Chemical Industry (MCI). The announcement was made in Beijing at the National People's Congress by Luo Gan, secretary-general of the State Council, China's highest decisionmaking body. A total of 11 national ministries are being abolished, and other government organizations are being restructured. Luo explained that as the economy is liberalized, it is necessary to end direct management of enterprises by specialized ministries. Theoretically, MCI was in charge of managing China's chemical industry, with one large exception—the petrochemical sector belonging to China National Petrochemical Corp. (Sinopec). MCI has about 350 staffers in Beijing, one source says. MCI combined some production and regulatory functions, but it did not direcdy control how its companies were run. "To some extent, I think that MCI has been a rather sophisticated lobbying machine for the chemical industry rather than a management operation," says Guy Clayton, a consultant who a year ago told C&EN of MCFs likely demise. Clayton, the U.K.- and Switzerland-based president of China Strategic Advisory Services, notes, "MCI kept its act together somewhat better than most because it's in strategic areas, particularly as far as agrochemicals and fertilizers are concerned." Thus, the organization had some clout. And Clayton, who until late 1996 ran the Greater China operations of the company then called Ciba-Geigy, expects that MCFs functions will continue to be carried out by many of the same people, just shifted to different organizations. In fact, a new office called Bureau of MARCH 16, 1998 C&EN 9
n e w s of t h e w e e k the Chemical Industry is planned. It will combine the regulatory functions of MCI, Sinopec, and China National Petroleum & Natural Gas Corp., according to observers. It will report to the State Economic & Trade Commission. The bureau is in line with the general trend in China toward superministries similar to Japan's Ministry of International Trade & Industry (MITT), says Makoto Takeda, a researcher at DIA Martech Research in Tokyo who is currently updating a report on China's petrochemical industry. Below this superministerial structure, he expects two very large chemical groups similar to Sinopec to emerge from the restructuring process. One group would be in the north, and the other in the south. So far, this supposition is based on "rumors." However, "it is 70% sure," he adds. The whole process will take about three years, he believes. Creating large chemical groups made up of weak and stronger firms may not be a good idea, cautions Clayton. "There are some very good industrialists and industrial concerns in China. I wouldn't have thought you would want to hamper them with less efficient ones," he says. Werner J. Wittlin, managing director of Clariant in Hong Kong, says it is too early to tell whether the Swiss
