Multilevel Storage in N-Doped Sb 2 Te 3 -Based Lateral Phase Change Memory with an Additional Top TiN Layer

Abstract

In this study, we present the physical images of multilevel storage (MLS) in both vertical and lateral phase change memory (PCM) devices and investigate MLS in a lateral PCM device with an additional top heater (LTH-PCM). The active layers above two lateral electrodes consist of a 50-nm-thick TiN layer as a top heater and a 150-nm-thick N-doped Sb 2 Te 3 layer. A number of distinct intermediate levels are obtained by current sweeping or pulse application. According to our analysis, MLS in our devices results mainly from the gradual crystallization between electrodes by Joule heating.