PROGRESS TOWARDS A DICK TRACY WATCH. Introduced in a Jan. 13, 1946 comic strip, the Dick Tracy watch is a techie's dream: it is a two-way, voice-activated video phone that fits around a wrist. In work that may lead to some components for a real-life Dick Tracy watch, Peter Gammel and his colleagues at Bell Labs/Lucent Technologies have constructed a tiny (100-micron) pyramid-shaped microphone on a silicon chip. According to Gammel, this is the first microphone built by surface micromachining techniques, in which various thin films are deposited on a silicon surface and some of the features are etched away to result in movable parts. This process is to be distinguished from bulk micromachining, in which features are carved out of a silicon surface itself. The researchers have also built a very small rf filter, which blocks unwanted radio frequencies and prevents signals from a phone's transmitter from disrupting its receiver. Made of aluminum nitride on a silicon surface, it is 100 times smaller than conventional ceramic filters, by far the largest single component in a cell phone. The Bell Labs researchers also built a micron-scale version of an inductor, a simple loop of wire that helps determine the proper frequency for communications. Most important of all, these components can all be built on the same silicon chip. Describing these results at the New York State section meeting of the APS held at Lucent last week, Gammel speculates that all of the components for a Dick Tracy watch should be technologically available by 2005. (See figure at Physics News Graphics)