Monday, December 26, 2005

"CHIPS: EU group researches one-chip phone"

In search of a single-chip cell phone, researchers worldwide are seeking alternatives to the many discrete front-end surface-acoustic-wave filters (SAWs) and other tunable radio frequency (RF) components required by today's communications devices. Now the European Union is proposing to use nanostructured ferroelectric films to integrate tunable microwave devices onto silicon-based microwave communications devices. The EU's Nanostar project ( is a three-year effort aimed at bringing the electronics industry one step closer to a single-chip cell phone. SAW devices have replaced bulk ceramic and quartz as microwave filters, correlators and modulators. But since they are not fabricated on silicon, Philips and others have turned to bulk acoustic-wave-devices that can be fabricated on silicon. But the Nanostar program aims to demonstrate that ferroelectric films can offer lower cost and power as well as new performance capabilities. Ferroelectric films are already being integrated into silicon-based memory chips as the capacitors for bit cells, but they can also be used in an analog mode as voltage-controlled capacitors (varactors) that are useful in tunable microwave components. However, the Nanostar program aims to exploit the other properties of ferroelectrics to create unique devices that someday could enable a single-chip cell phone.