Field effect in GeTe thin films

Phase change memory is a promising candidate to replace common memory technologies such as Flash and DRAM due to its fast switching and excellent scaling perspectives. To improve memory density even further, it was proposed to combine the switchable resistor and the cell selection transistor in a single device. Current control by applying gate voltages has been demonstrated in the works of Yin et al. for Ge2Sb2Te5. Recently, switching within a few nanoseconds has been demonstrated on a different material, GeTe. We therefore studied the field effect in thin films of amorphous GeTe. Dedicated transistor devices were prepared, and the transfer characteristics of these devices were measured as a function of temperature and film thickness. Furthermore, time-dependent behavior was observed and analyzed.