Carbon ion implantation as healing strategy for improved reliability in phase-change memory arrays

In this paper we investigate the effect of Carbon ion implantation in Ge2Sb2Te5 based Phase-Change Memory (PCM) targeting reliability improvement in 4 kb memory arrays. We show how ion implantation by beam line allows to localize the Carbon in a specific volume of the active layer, demonstrating that a low C concentration (lower than 5 at. %) can be achieved with a high control thanks to dose monitoring. We evidence an outstanding improvement of the PCM cell performances, in both single devices and 4 kb arrays, such as programming window widening and reduced variability of electrical parameters. We support our findings by TEM/EDS analyses demonstrating the healing effects of C ion implantation on interfaces and on retarding the phase-change layer segregation mechanisms.