Characteristic improvement of Ge 1Se 1Te 2 phase change memory by the heating method and the device structure change

Abstract

In this paper, we propose an advanced material device with a new structure in order to overcome a problem of high programming currents that the conventional phase-change random access memory (PRAM) device, Ge 2Sb 2Te 5 PRAM device, currently has. To minimize set/reset currents, a cell structure has to be optimized by a proper device process. We have investigated a phase transition behaviors with experiments under structural change. As a result, we have observed that the programming voltage and the writing current of Ge 1Se 1Te 2 material are preferable than those of Ge 2Sb 2Te 5 material. It is known that phase change properties of Ge 1Se 1Te 2 materials vary depending on the presence of heater electrode layers. We found out that it is effective to use a multi-layer structure (Ge 2Sb 2Te 5 layer inserted into Ge 1Se 1Te 2 layer) in order to reduce the programming voltage. The multi-layered device showed improved performance than single-layered Ge 1Se 1Te 2 PRAM device.