Innovative Multilayer OTS Selectors for Performance Tuning and Improved Reliability

Abstract

In this paper, we investigate an innovative Ovonic Threshold Switching Selector (OTS) based on Multilayer structure (ML). Thanks to physico-chemical analysis and electrical characterization we show how MLs properties and structure can be tuned thanks to the engineering of each individual layer stoichiometry, thickness and interfaces. Ge/N-doped SbSe-based MLs OTS are analyzed by FTIR and Raman spectroscopy revealing the structural features present in the as-deposited materials and the strong interaction among individual layers at interfaces. We demonstrate the improved variability control of electrical parameters wrt standard OTS achieved by co-sputtering technique, and the high endurance capability of MLs OTS up to more than 2•10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> cycles with stable nA leakage current. Moreover, we show how Ge-N bonds play a huge role on OTS thermal stability at 400°C and how they can be tuned more easily in ML OTS. These developments pave the way towards a new class of OTS materials and their engineering, ensuring high temperature stability and best tuning of electrical performances.