Abstract: A device that may be used for a phase change random access memory in a semiconductor device and a manufacturing method thereof are provided. The device includes a phase change unit and two sidewall electrodes respectively located on two opposite sidewalls of the phase change unit. The phase change unit includes a three layer structure, in which a phase change material layer is positioned between a top insulating material layer and a bottom insulating material layer. The first sidewall electrode and the second sidewall electrode are in contact with two opposite end faces of the phase change material layer. The contact area between electrode and phase change material is reduced, thereby obtaining a relatively small drive current and meeting a demand that the integrated level of such a device is increasingly enhanced.