In the semiconductor world, one of the biggest performance bottlenecks is the link between separate chips on a circuit board. The more circuitry you can stuff onto a single chip, the faster it will perform and the less power it will draw-a key consideration in today's tiny consumer electronics. Large, complex chips, however, have a high failure rate during production, and the main alternative-bonding smaller chips together-requires high temperatures, which lead to defects after cooling. Now Ziptronix, a commercial spinoff of the Research Triangle Institute, has hit upon a better way. The Research Triangle Park, NC-based company has succeeded in pressing together two wafers (the thin sheets of semiconductor material on which computer chips are grown and etched) at room temperature, bonding the chips on one to the surface of the other. Cutting away the donor wafer leaves its chips embedded on the host. Connect the resulting circuits and you have twice the transistors on one chip. The process can be repeated as many times, and with as many different semiconductors (gallium arsenide, indium phosphide), as required. Products built using the technology could be on the market by early 2002.