Multilayer Structure in SeAsGeSi-based OTS for High Thermal Stability and Reliability Enhancement

In this paper, we present an innovative Multilayer SeAsGeSi-based Ovonic Threshold Switching (OTS) Selector targeting high reliability for Crossbar arrays. We compare our Multilayer (ML) OTS with SeAsGeSi-based bulk alloy (SAGS). We demonstrate the high thermal stability of the ML stack against the Back-End-of-Line (BEOL) thermal budget as well as the reduction of the device-to-device variability and reliable switching operations up to 300°C. We study by Raman and FTIR spectroscopy the integrity of the ML OTS material after an annealing of 3 hours at 400° C. SeAsGeSi Multilayer OTS delays crystallization mechanism along cycling. We finally report the successful co-integration of our ML with Phase-Change Memory technology.