Phase change RF switches with fCO exceeding 10 THz

We report on an emerging class of non-volatile solid-state RF switch that can routinely achieve cutoff frequencies above 10 THz. The switch element is constructed of GeTe, a phase change chalcogenide that can be thermally cycled between a conductive and a resistive state. A resistive heater is located proximate the switch element, such that it is thermally coupled to the switch but electrically isolated. This structure affords excellent electrical isolation of the switch resulting in its high FCO. This paper will discuss the topology of the switch and various design tradeoffs for optimizing switch resistance, switching power, monolithic integration with CMOS and other design objectives. Published system-level demonstrations of using these switches to reconfigure real RF systems will be reviewed and an outlook for the future will be provided.