Seminar LMGP - 05/02/2019 - KIM Youngjin

Abstract
The formation of conductive filaments (CFs) within an insulating medium of resistive random access memory (RRAM) is critical factor in the determining memory performance of the filamentary-based RRAM. However, random formation and additional growth of CFs have still deteriorated the reliability and uniformity in resistive switching (RS) behavior. Herein, we demonstrate that the filament grows up in limited region via selective oxidation of structured active electrode arrays which have a high-quality tip and uniform size fabricated by template-stripping method. Since the tip-enhanced electric fields and high surface energy can facilitate the ionization of active metal and their ion-hopping of generated metal ion, the nucleation and growth of CF occurs only within tip region of metal pyramid electrode. Moreover, we confirmed that the operating parameters including Forming, SET, and RESET voltages for pyramid-based cell could be controlled with very narrow and low range. The selective oxidation and formation of CF were directly observed using electron microscopy analyses with elementary analysis of CF and were confirmed using theoretical simulation. When the practical estimation for the controlled formation of CF were carried out, the device exhibited excellent uniform and reliable cell-to-cell performance. This approach will promote the practical application in RRAM fields.