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

Abstract

In this paper we investigate the effect of Carbon ion implantation in Ge2Sb2Te5 based Phase-Change Memory (PCM) targeting reliability improvement in 4kb 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 4kb 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.