Out-of-plane and inline RF switches based on Ge<inf>2</inf>Sb<inf>2</inf>Te<inf>5</inf> phase-change material

Abstract

We present the fabrication and characterization of novel RF switches based on Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> (GST) phase change material. Such ohmic devices show non-volatile switching with resistivity changes up to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> as the material is transforming between the amorphous and the crystalline state by either applying a voltage pulse or direct heating. We investigated the RF properties and power handling of such devices in two configurations: out-of-plane (GST material between two electrodes) and inline switches. For a directly heated 10-μm length inline switch we measured an on-state resistance of 7 Ω, and an off-state capacitance and resistance of 13.7 fF and 6.47 MΩ, respectively, resulting in a cut-off frequency of ~1.6 THz.