The effect of doping Sb on the electronic structure and the device characteristics of Ovonic Threshold Switches based on Ge-Se

Abstract

The Ovonic Threshold Switch (OTS) based on an amorphous chalcogenide material has attracted much interest as a promising candidate for a high-performance thin-film switching device enabling 3D-stacking of memory devices. In this work, we studied on the electronic structure of amorphous Sb-doped Ge0.6Se0.4 (in atomic mole fraction) film and its characteristics as to OTS devices. From the optical absorption spectroscopy measurement, the band gap (Eg) was found to decrease with increasing Sb content. In addition, as Sb content increased, the activation energy (Ea) for electrical conduction was found to decrease down to about one third of Eg from a half. As to the device characteristics, we found that the threshold switching voltage (Vth) drastically decreased with the Sb content. These results, being accountable in terms of the changes in the bonding configuration of constituent atoms as well as in the electronic structure such as the energy gap and trap states, advance an effective method of compositional adjustment to modulate Vth of an OTS device for various applications.

Toward ultimate nonvolatile resistive memories: The mechanism behind ovonic threshold switching revealed

“…with previous studies (20,35). The introduction of Sb has nevertheless two major drawbacks that limit its potential for applications.…”

Dependence of Switching Probability on Operation Conditions in GexSe1–xOvonic Threshold Switching Selectors

“…The statistical analysis of the OTS switching voltage and switching time and their correlation is therefore critically important for choosing suitable operation conditions for the 1S1R structure. Despite recent efforts in tuning the material composition and process to improve the performance [10][11][12][13][14][15], an experimental characterization method is still lacking for quantitatively evaluating the switching probability and its dependence on the operation conditions, which is the essential information required for designing the 1S1R array.…”

Investigation of the Atomic Structure of Ge-Sb-Se Chalcogenide Glasses

“…Ternary Ge-Sb-Se glasses are promising materials for infrared optical fibers application because of their high transparency in the key region and good thermal, mechanical, and chemical properties. The physicochemical, elastic-plastic, and optical properties of the ternary Ge-Sb-Se chalcogenide system have been intensively studied [5][6][7][8][9][10][11][12][13], and the influence of Ge/Sb ratio on the optical, electronic, and microstructural properties of Ge-Sb-Se system has been considered. A common and useful parameter for the explanation of the compositional dependence on the physical properties is the coordination number Z of covalent bonds per atom, characterizing the structural atomic units [5,13,14].…”