Filamentary-Based Resistive Switching

Abstract

Based on ionic motion, filamentary-based resistive switches are an important class of emerging electronic devices. This chapter describes their basic operative principles and provides the reader with a sufficient basis to follow the experimental work of this dissertation. After a brief introduction on the resistive switching (RS), conductive bridge random access memory (CBRAM) and valence change memory (VCM) are introduced. The devices investigated in this work, namely Cu-Al{\$}{\$}{\_}{\{}2{\}}{\$}{\$}2O{\$}{\$}{\_}{\{}3{\}}{\$}{\$}3for CBRAM and Hf/HfO{\$}{\$}{\_}{\{}2{\}}{\$}{\$}2for VCM, are introduced together with their major figures of merit and fabrication details. Section 2.2 elucidates the electrochemical processes governing the filament formation in CBRAM, and Sect. 2.3 the relevant electron transport in VCM. In Sects. 2.2.4 and 2.3.4 we introduce some of the latest solutions proposed for the optimization of the memory devices. The quantum-point-contact (QPC) description of the conductive filament (CF) is treated in Sect. 2.3.3. Finally, in Sect. 2.4, a short review of the wide literature available on the filament observation is reported as reference for the original experimental results presented in the following chapters.