Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions

This thesis reports a study of the resistive switching phenomena in oxide based material systems, practically hafnium and graphene oxide based Resistive Random Access Memories (RRAMs), in aspects of device fabrication, electrical and physical characterization, and theoretical calculation. Both hafni...

Full description

Saved in:
Bibliographic Details
Main Author: Wang, Zhongrui
Other Authors: Hong-yu Yu
Format: Theses and Dissertations
Language:English
Published: 2014
Subjects:
Online Access:https://hdl.handle.net/10356/61763
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-61763
record_format dspace
spelling sg-ntu-dr.10356-617632023-07-04T16:27:50Z Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions Wang, Zhongrui Hong-yu Yu Jun Wei Zhu Weiguang School of Electrical and Electronic Engineering A*STAR Singapore Institute of Manufacturing Technology Microelectronics Centre DRNTU::Engineering::Electrical and electronic engineering::Electronic apparatus and materials This thesis reports a study of the resistive switching phenomena in oxide based material systems, practically hafnium and graphene oxide based Resistive Random Access Memories (RRAMs), in aspects of device fabrication, electrical and physical characterization, and theoretical calculation. Both hafnium and graphene oxide based RRAMs have been fabricated. Through variation of the configuration of material systems and deposition techniques, boosts of performance in terms of uniformity, forming-free property and self-compliance are realized in the hafnium oxide based RRAM. On the other hand, impact of electrodes, critical role for graphene oxide RRAM, has been studied for its influence to the switching directions. Electrical and physical characterization are employed to unravel the underlying transport and switching mechanisms. Frequency and temperature dependent dielectric loss characterization, implementing on the hafnium oxide RRAM, provides the evidence of the existence of small polaron adiabatic hopping in the high resistance state, consistent with the analysis of activation energy and field dependence. On the other hand, a weak metallic nature in transport is identified in the low resistance state. In graphene oxide RRAM, same technique reveals the fact that the combination of both oxygen related functional groups absorption/release and electrode metal ions diffusion are responsible for the multidirectional switching. Theoretical calculation, using hybrid functional in first principle simulation, is performed to interpret the observed metal-insulator transitions in the hafnium oxide based RRAM. Computational evidence is found for oxygen vacancy-bound small polarons migration and Mott type localization-delocalization transition. Adiabatic polaron hopping between equivalent threefold oxygen vacancies are of anisotropic barriers, in both the bulk and (-111) surface slab models, consistent with the characterization findings. Phonon correlation to the hopping of the small polaron is explored where the important roles of the vacancy neighboring threefold oxygen atoms are unveiled. ELECTRICAL and ELECTRONIC ENGINEERING 2014-09-12T06:57:28Z 2014-09-12T06:57:28Z 2014 2014 Thesis Wang, Z. (2014). Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/61763 10.32657/10356/61763 en 194 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Electrical and electronic engineering::Electronic apparatus and materials
spellingShingle DRNTU::Engineering::Electrical and electronic engineering::Electronic apparatus and materials
Wang, Zhongrui
Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
description This thesis reports a study of the resistive switching phenomena in oxide based material systems, practically hafnium and graphene oxide based Resistive Random Access Memories (RRAMs), in aspects of device fabrication, electrical and physical characterization, and theoretical calculation. Both hafnium and graphene oxide based RRAMs have been fabricated. Through variation of the configuration of material systems and deposition techniques, boosts of performance in terms of uniformity, forming-free property and self-compliance are realized in the hafnium oxide based RRAM. On the other hand, impact of electrodes, critical role for graphene oxide RRAM, has been studied for its influence to the switching directions. Electrical and physical characterization are employed to unravel the underlying transport and switching mechanisms. Frequency and temperature dependent dielectric loss characterization, implementing on the hafnium oxide RRAM, provides the evidence of the existence of small polaron adiabatic hopping in the high resistance state, consistent with the analysis of activation energy and field dependence. On the other hand, a weak metallic nature in transport is identified in the low resistance state. In graphene oxide RRAM, same technique reveals the fact that the combination of both oxygen related functional groups absorption/release and electrode metal ions diffusion are responsible for the multidirectional switching. Theoretical calculation, using hybrid functional in first principle simulation, is performed to interpret the observed metal-insulator transitions in the hafnium oxide based RRAM. Computational evidence is found for oxygen vacancy-bound small polarons migration and Mott type localization-delocalization transition. Adiabatic polaron hopping between equivalent threefold oxygen vacancies are of anisotropic barriers, in both the bulk and (-111) surface slab models, consistent with the characterization findings. Phonon correlation to the hopping of the small polaron is explored where the important roles of the vacancy neighboring threefold oxygen atoms are unveiled.
author2 Hong-yu Yu
author_facet Hong-yu Yu
Wang, Zhongrui
format Theses and Dissertations
author Wang, Zhongrui
author_sort Wang, Zhongrui
title Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
title_short Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
title_full Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
title_fullStr Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
title_full_unstemmed Advanced oxide based resistive random access memories (RRAMs) : switching mechanisms and material solutions
title_sort advanced oxide based resistive random access memories (rrams) : switching mechanisms and material solutions
publishDate 2014
url https://hdl.handle.net/10356/61763
_version_ 1772825520899096576