Abstract
We studied phase-change channel transistor memory devices with an ultrathin Ge2Sb2Te5 chalcogenide film channel and tried to demonstrate two combined functions (memory: resistance change and selection: channel current control) by annealing in this paper. Drain–source resistance can be markedly decreased by 2–3 orders of magnitude after annealing due to the phase change from the amorphous to crystalline phases. A channel current control effect in which the drain current decreases with the gate voltage was clearly observed in 10- and 20-nm-thick Ge2Sb2Te5 devices. The absolute channel current modulation by the gate voltage in the crystalline state is much stronger than that in the amorphous state. Furthermore, the channel current control ability in devices with thin Ge2Sb2Te5 is stronger than that in devices with thick Ge2Sb2Te5. The channel current control effect might result from the potential change of the ultrathin Ge2Sb2Te5 channel by the gate voltage.