title: Nanoscale multilevel switching in Ge2Sb2Te5 thin film with conductive atomic force microscopy.
abstract: We demonstrate three-level data storage in amorphous Ge2Sb2Te5 (GST) thin film by conductive atomic force microscopy (C-AFM). Due to the high resolution and current sensitivity of AFM, the electrical properties of GST are investigated in the nanoscale. By applying an electric field between an AFM probe tip and the GST surface, well-resolved threshold switching and memory switching are obtained successively in a current-voltage sweeping. Correspondingly, three states with high, intermediate and low resistances, which are assigned data values '0', '1' and '2' respectively, are observed in an IV-spectrum. The electrical resistance of GST thin film decreases by over two orders of magnitude in both switching processes, which provides a clear contrast to distinguish the three logical states. We also discuss the threshold electrical field of threshold switching in the amorphous GST thin film. Nanoscale conductive marks in the amorphous ON state and crystalline state are successfully fabricated by applying IV-spectra with different voltage ranges on the GST thin films.
authors.affiliation: School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures of National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China. School of Electronics and Information Engineering, Anhui University, Hefei 230601, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Yao
authors.initials: Y
authors.lastname: Yu
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Ma
authors.forename: Kunji
authors.initials: K
authors.lastname: Chen