论文部分内容阅读
In recent years,many new types of memory have been proposed to replace conventional flash memories.In these emerging memories,phase-change memory(PCM)has attracted much attention in the world [1].It is based on fast and reversible transformation between amorphous and crystalline phases,which have very different electrical conductivities.It has many advantages such as high speed,low power,good endurance,and high scalability.However,the high operation current of PCM is a great barrier for its mass production.And,previous technologies to reduce operation current are strictly dependent on lithography.To further decrease the operation current,it is necessary to find some new solutions,which is not limited to the current lithography technology.In this study,we proposed a lithography-independent technology and intensively investigated our proposed nano-contact phase-change memory(nano-C PCM)with incorporated nanostructures and high-resistivity nanolayer for reducing reset current.We experimentally demonstrated that the high resistivity was able to be obtained by doping N into the conventional Ge2Sb2Te5 phase change material.The analysis based on finite element method exhibited that the current density in the nano-C PCM could be locally enhanced to about 2 times that of both conventional and nanolayer PCM devices.The results exhibited that the localization of Joule heating was caused by the lithography-independent miniaturization of contact area,which could be realized by self-assembly of block copolymer and subsequent etching.We demonstrated that the reset operation current was significantly deceased to about 8.2%of that of the conventional PCM device because of the high efficiency of heating.