[Show abstract][Hide abstract] ABSTRACT: Stackable select devices such as the oxide p-n junction diode and the Schottky diode (one-way switch) have been proposed for non-volatile unipolar resistive switching devices; however, bidirectional select devices (or two-way switch) need to be developed for bipolar resistive switching devices. Here we report on a fully stackable switching device that solves several problems including current density, temperature stability, cycling endurance and cycle distribution. We demonstrate that the threshold switching device based on As-Ge-Te-Si material significantly improves cycling endurance performance by reactive nitrogen deposition and nitrogen plasma hardening. Formation of the thin Si3N4 glass layer by the plasma treatment retards tellurium diffusion during cycling. Scalability of threshold switching devices is measured down to 30 nm scale with extremely fast switching speed of ~2 ns.
[Show abstract][Hide abstract] ABSTRACT: In recent years, resistance changes random access memory (RRAM) which shows reversible bistable resistance states by applied voltage has been studied as one of the alternatives of next-generation nonvolatile memory due to its excellent device characteristics including scalability, speed, and retention. Here, we report on the noncharge-based NiO RRAM device characteristics with load resistor as well as the simulation results of controlled conducting filament configuration. The RRAM device with load resistor showed super performances including highly reduction of switching current (~1 order) and significantly improved switching voltage distribution (30% reduction).
[Show abstract][Hide abstract] ABSTRACT: An alternative approach of controlling bistable resistance switching in NiO was investigated. By fabricating a multilayer structure of three NiOx layers with varying oxygen content, bistable resistance switching could be localized. By varying the enveloping oxygen partial pressure during NiOx layer deposition from 10% to 30%, improved resistance and switching voltage distribution from cycle to cycle was achieved. In addition, more localized switching could emulate sub-100-nm-sized cells showing decreased reset current values on the order of 100 A. X-ray photon spectroscopy analysis shows a clear grading near the interfaces of successive NiO layers.