Electrical Switching Studies of Amorphous Ge1Se1Te2 Thin Film for a High-Performance Nonvolatile Phase-Change Memory

概要

論文の詳細を見る
In the present work, we studied the changes in the electrical conductivity occurring in a new composition of amorphous Ge1Se1Te thin film for a high-performance nonvolatile phase-change memory. A phase-change random access memory (PRAM) device without an access transistor is successfully fabricated with the Ge1Se1Te2 phase-change resistor, which has a much higher electrical resistivity than that of conventional Ge2Sb2Te5, and its electric resistivity can be varied by the factor of $10^{5}$, related to the degree of crystallization. Chalcogenide Ge1Se1Te2 thin film of 100 nm thickness was formed by vacuum deposition at $1.5\times 10^{-5}$ Torr. The static mode switching characteristics are tested for the 100 μm-sized Ge1Se1Te2 PRAM device. In the first sweep, the amorphous Ge1Se1Te2 thin film showed a high resistance state in the low voltage region. However, when it reached the threshold voltage, $V_{\text{th}}$, the electrical resistance of the device was drastically reduced through the formation of an electrically conducting path. The results of pulsed mode switching of the 20 μm-sized Ge1Se1Te2 PRAM devices show that the reset process of the device was accomplished with an 80 ns–8.6 V pulse and the set process of the device was accomplished with a 200 ns–4.3 V pulse.
2006-06-30