Exploration of electrode-modulated memory and threshold switching behaviour in Se-Te-Sn thin film devices

Abstract

Due to their potential use in high-density, three-dimensional stackable cross-point array structures, the electrical switching ability of chalcogenide glasses has captured a lot of attention. Herein, the switching behaviour of unique Se<inf>86-x</inf>Te<inf>14</inf>Sn<inf>x</inf> (x = 0, 2, 4, 6) chalcogenide glassy alloys in the form of a thin film were investigated. The electrode modulated dual functionality in switching was achieved by employing Aluminium (Al) and Silver (Ag), as top electrodes. The films with Al/Se<inf>86-x</inf>Te<inf>14</inf>Sn<inf>x</inf>/Al interface exhibited memory-type switching due to the phase-changing properties of the material. The threshold voltage (V<inf>th</inf>) decreased linearly from 12.75 V to 4.2 V at room temperature as Sn concentration in the glass increased. On the other hand, when the top electrode was replaced with Ag, the Ag/Se<inf>86-x</inf>Te<inf>14</inf>Sn<inf>x</inf>/Al interface acted as a programmable metallization cell (PMC) showing threshold-switching properties. Ag/Se<inf>82</inf>Te<inf>14</inf>Sn<inf>4</inf>/Al thin film of thickness 200 nm showed promising results as a material for a unidirectional selector, due to the formation of temporary Ag filament inside chalcogenide material. The composition showed high selectivity (∼104), high endurance (>104 cycles), and low threshold voltage (∼1.6 V). The ability of the composition to exhibit electrode-dependent memory and threshold-switching phenomena makes the material an interesting case. © 2024 Elsevier B.V.