Multilevel Storage in N-Doped Sb2Te3-Based Lateral Phase Change Memory with an Additional Top TiN Layer

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 Sb2Te3 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.

[1]  Rajeev Ahuja,et al.  Structure of phase change materials for data storage. , 2006, Physical review letters.

[2]  Bomy Chen,et al.  Multilevel Data Storage Characteristics of Phase Change Memory Cell with Doublelayer Chalcogenide Films (Ge2Sb2Te5 and Sb2Te3) , 2007 .

[3]  Sumio Hosaka,et al.  Lateral SbTeN based multi-layer phase change memory for multi-state storage , 2007 .

[4]  You Yin,et al.  Multilevel Storage in Lateral Top-Heater Phase-Change Memory , 2008, IEEE Electron Device Letters.

[5]  Sumio Hosaka,et al.  Characterization of nitrogen-doped Sb2Te3 films and their application to phase-change memory , 2007 .

[6]  S. Hosaka,et al.  Prototype of Phase-Change Channel Transistor for Both Nonvolatile Memory and Current Control , 2007, IEEE Transactions on Electron Devices.

[7]  K. Nakayama,et al.  Submicron Nonvolatile Memory Cell Based on Reversible Phase Transition in Chalcogenide Glasses , 2000 .

[8]  Sumio Hosaka,et al.  Dependences of Electrical Properties of Thin GeSbTe and AgInSbTe Films on Annealing , 2005 .

[9]  Bingchu Cai,et al.  Design of multi-states storage medium for phase change memory , 2007 .

[10]  Stanford R. Ovshinsky,et al.  Amorphous semiconductors for switching, memory, and imaging applications , 1973 .

[11]  Sumio Hosaka,et al.  Ultramultiple-level storage in TiN∕SbTeN double-layer cell for high-density nonvolatile memory , 2008 .

[12]  Sumio Hosaka,et al.  Scanning electron microscope for in situ study of crystallization of Ge2Sb2Te5 in phase-change memory. , 2007, The Review of scientific instruments.

[13]  Bingchu Cai,et al.  Stacked chalcogenide layers used as multi-state storage medium for phase change memory , 2006 .

[14]  M. Lankhorst,et al.  Low-cost and nanoscale non-volatile memory concept for future silicon chips , 2005, Nature materials.

[15]  S. Ovshinsky.  Reversible Electrical Switching Phenomena in Disordered Structures , 1968 .

[16]  Sumio Hosaka,et al.  A Novel Lateral Phase-Change Random Access Memory Characterized by Ultra Low Reset Current and Power Consumption , 2006 .