Number 97 (Story #3), October 6, 1992 by Phillip F. Schewe and Ben Stein DIAMOND-FILM SEMICONDUCTOR devices may someday surpass silicon-based devices for speed and be able to operate at high temperatures. Scientists can now grow diamond films by planting tiny diamond seeds in a silicon wafer pocked with pyramidal pits. The pits line up the seeds' facets to within a fraction of a degree so that a subsequent low-pressure epitaxial laying down of atoms results in a nearly-single-crystal sheet of diamond (with sizes up to an inch in diameter). Doped with boron, the diamond film is semiconducting and can operate without breaking down at higher levels of voltage, power, and temperature (up to 700 C) than silicon or gallium-arsenide. This suggests that diamond circuits could be smaller and therefore faster. Device applications must await improvements in the ability to grow larger films. Also problems in etching circuit patterns and in controlling impurities must be overcome. (Scientific American, October 1992.)