Highly scalable nonvolatile resistive memory using simple binary oxide driven by asymmetric unipolar voltage pulses

Simple binary-TMO (transition metal oxide) resistive random access memory named as OxRRAM has been fully integrated with 0.18/spl mu/m CMOS technology, and its device as well as cell properties are reported for the first time. We confirmed that OxRRAM is highly compatible with the conventional CMOS process such that no other dedicated facility or process is necessary. Filamentary current paths, which are switched on or off by asymmetric unipolar voltage pulses, made the cell properties insensitive to cell or contact size promising high scalability. Also, OxRRAM showed excellent high temperature performance, even working at 300/spl deg/C without any significant degradation. With optimized TMO material and electrodes, OxRRAM operated successfully under 3V bias voltage and 2mA switching current at a TMO cell size smaller than 0.2/spl mu/m/sup 2/.

Introduction

Resistive memories, which can vary their resistance depending on applied voltage, were intensively studied from the 1960s to early 1980s for device applications (1). For example, chalcogenide materials, semiconductors, various kinds of oxides and nitrides, and even organic materials were found to have resistive memory properties. However, high operation voltage and current, poor endurance, and low film handling technique made the resistive memory unfavorable in comparison with capacitive memories.