AVS 58th Annual International Symposium and Exhibition
    Electronic Materials and Processing Division Tuesday Sessions
       Session EM-TuA

Paper EM-TuA11
Nonvolatile Memresistive Nano-Crossbar Switches in Pt/Ta2O5/Cu Solid Electrolytes

Tuesday, November 1, 2011, 5:20 pm, Room 210

Session: High-k Dielectrics for MOSFETs Part 2
Presenter: Pragya Shrestha, National Institute of Standards and Technology (NIST)
Authors: P.R. Shrestha, National Institute of Standards and Technology (NIST)
K.P. Cheung, National Institute of Standards and Technology (NIST)
H. Baumgart, Old Dominion University
Correspondent: Click to Email
Metal filament resistive memory is an excellent candidate for a nanoscale crossbar switch, and such two terminal “memresistive” devices are being considered for next-generation non-volatile memory due to the inherent simplicity, scalability and low cost (1). Additionally, these devices show potential to replace static random access memory (SRAM) as high performance switches for reconfigurable devices .

Memresistive devices operate by changing resistance from high (Roff) to low (Ron) values in response to an applied voltage. Despite a tremendous amount of work in the scientific literature, the actual underlying switching mechanism has yet to be fully explained. Few studies, most of which lack measurement details, have reported on the transient current response and high speed switching characteristics of memresistive devices. The papers suggest the presence of the variety of active current and thermal dissolution of the low resistance filament while switching OFF. The switching ON has been attributed to the movement of the metal ions towards the cathode and being neutralized by the electrons to form the metal filament. Transient current measurements for switching ON have not yet been analyzed in detail in the literature. Another crucial problem in measurements of these devices is due to the preferred values of Ron(<1kΩ) and Roff(>1GΩ). Thus the key obstacle preventing fundamental understanding has been the lack of reliable and accurate measurements of the transient response while switching ON (from Roff to Ron). In this work, we developed a new measurement capability that enables reliable and accurate investigation of the transient switching response, monitoring change from low Ron to high Roff.

In order to address the need to reliably and accurately monitor the device I-V transient response extremely fast, we have designed an amplifier with low-gain and high bandwidth (1.7 GHz) to accommodate much faster (and realistic) “program” voltage pulses. For switching purposes, this amplifier allows for fast transient current monitoring during programming with proficiency but not limited to follow 2 nsec of pulse rise time. The high gain bandwidth of the amplifier allows us to monitor change from low current (Roff) to high current (Ron) accurately.

1. R. Waser, R. Dittmann, G. Staikov, K. Szot, Advanced Materials 21, 2632 (2009).