650 ps SET speed in Ge_(2)Sb_(2)Te_(5)phase change memory induced by TiO_(2) dielectric crystal plane

Crystallization speed of phase change material is one of the main obstaclesfor the application of phase change memory(PCM)as storage classmemory in computing systems,which requires the combination ofnonvolatility with ultra-fast operation speed in nanoseconds.Here,wepropose a novel approach to speed up crystallization process of the onlycommercial phase change chalcogenide Ge_(2)Sb_(2)Te_(5)(GST).By employingTiO_(2)as the dielectric layer in phase change device,operation speed of650 ps has been achieved,which is the fastest among existing representativePCM,and is comparable to the programing speed of commercialdynamic random access memory(DRAM).Because of its octahedralatomic configuration,TiO_(2)can provide nucleation interfaces for GST,thus facilitating the crystal growth at the determinate interface area.Ti–O–Ti–O four-fold rings on the(110)plane of tetragonal TiO_(2)is critical forthe fast-atomic rearrangement in the amorphous matrix of GST thatenables ultra-fast operation speed.The significant improvement of operationspeed in PCM through incorporating standard dielectric materialTiO_(2)in DRAM paves the way for the application of phase change memoryin high performance cache-type data storage.