Query: Modeling of electron conduction in contact resistive random access memory devices as random telegraph noise

Candidate papers:

abstract: The intense development and study of resistive random access memory (RRAM) devices has opened a new era in semiconductor memory manufacturing. Resistive switching and carrier conduction inside RRAM films have become critical issues in recent years. Electron trapping/detrapping behavior is observed and investigated in the proposed contact resistive random access memory (CR RAM) cell. Through the fitting of the space charge limiting current (SCLC) model, and analysis in terms of the random telegraph noise (RTN) model, the temperature dependence of resistance levels and the high temperature data retention behavior of the contact RRAM film are successfully and completely explained. Detail analyses of the electron capture and emission from the traps by forward and reverse read measurements provide further verifications for hopping conduction mechanism and current fluctuation discrepancies.
author_names: Yuan Heng Tseng

Wen Chao Shen

Chrong Jung Lin
title: Modeling of electron conduction in contact resistive random access memory devices as random telegraph noise.
venue: Journal of applied physics
year: 2012

abstract: Single electron trapping/de trapping behavior is firstly observed and investigated in the contact resistive random access memory cell. By analyzing the random telegraph noise, the temperature dependency of resistance levels and the high temperature data retention behavior of the contact RRAM film are successfully explained. Detail analyses on the capture and emission of electrons in this contact RRAM cell provide further verifications for the proposed trap induced resistive switching model.
author_names: Yuan Heng Tseng

Wen Chao Shen

Chia-En Huang

Chrong Jung Lin

Ya-Chin King
title: Electron trapping effect on the switching behavior of contact RRAM devices through random telegraph noise analysis
venue: 2010 International Electron Devices Meeting
year: 2010

abstract: Variability in resistive random access memory cell has been one of the critical challenges for the development of high density RRAM arrays. While the sources of variability during resistive switching vary for different transition metal oxide films, the stochastic oxygen vacancy generation/recombination is generally believed to be the dominant cause. Through analyzing experimental data, a stochastic model which links the subsequent switching characteristics with its initial states of contact RRAM cells is established. By combining a conduction network model and the trap assisted tunneling mechanism, the impacts of concentration and distribution of intrinsic oxygen vacancies in RRAM dielectric film are demonstrated with Monte Carlo Simulation. The measurement data on contact RRAM arrays agree well with characteristics projected by the model based on the presence of randomly distributed intrinsic vacancies. A strong correlation between forming characteristics and initial states is verified, which links forming behaviors to preforming oxygen vacancies. This study provides a comprehensive understanding of variability sources in contact RRAM devices and a reset training scheme to reduce the variability behavior in the subsequent RRAM states.
author_names: Yun-Feng Kao

Wei-Cheng Zhuang

Chrong Jung Lin

Ya-Chin King
title: A Study of the Variability in Contact Resistive Random Access Memory by Stochastic Vacancy Model
venue: Nanoscale Research Letters
year: 2018

abstract: We investigated the low frequency noise (LFN) properties of the bipolar switching resistance random access memories (RRAMs) for the first time with amorphous TiOx based RRAM devices. The LFNs are proportional to 1/f for both high resistance (HRS) and low resistance states (LRS) The normalized noise in HRS is around an order of magnitude higher than that in LRS. The random telegraph noise (RTN) is observed only in HRS, which represents that the dominant trap causing the RTN becomes electrically inactive by being filled with electrons in LRS. The voltage dependence Si/I2 of shows that the noise can be used to elucidate the operation mechanism of RRAM devices.
author_names: Jung-kyu Lee

Hu Young Jeong

In-Tak Cho

Jeong Yong Lee

Sung-Yool Choi

Hyuck-In Kwon

Jongho Lee
title: Conduction and Low Frequency Noise Analysis in \hbox{Al}\alpha\hbox{ TiO}_{X}\hbox{Al} Bipolar Switching Resistance Random Access Memory Devices
venue: IEEE Electron Device Letters
year: 2010

abstract: A new type of true random number generator, based on the random telegraph noise of a contact resistive random access memory device, is proposed in this letter. The random number generator consists of only a simple bias circuit plus a comparator, leading to small circuit area and low power consumption. By realizing this generator by the 65 nm complementary metal oxide semiconductor logic process, the occupied area can be as low as 45 mm2, demonstrating substantial saving in the circuit area.
author_names: Chien-Yuan Huang

Wen Chao Shen

Yuan Heng Tseng

Ya-Chin King

Chrong Jung Lin
title: A Contact Resistive Random Access Memory Based True Random Number Generator
venue: IEEE Electron Device Letters
year: 2012

abstract: Low frequency noise (LFN) characteristics have been studied in polycrystalline TiOx based resistive random access memories (RRAMs) LFNs are proportional to 1/f in high resistance state (HRS) but those in low resistance state (LRS) are proportional to 1/f only in less than ~100 Hz. The normalized noise power in HRS is around three orders of magnitude higher than that in LRS. Bias dependence of 1/f noise shows that the current conduction mechanisms from noise measurements are consistent with those from the current voltage relationships in TiOx based unipolar RRAM devices.
author_names: Jung-kyu Lee

In-Tak Cho

Hyuck-In Kwon

Cheol Seong Hwang

Chan Hyeong Park

Jongho Lee
title: Relationship Between Conduction Mechanism and Low Frequency Noise in Polycrystalline \hbox{TiO}_{x} Based Resistive Switching Memory Devices
venue: IEEE Electron Device Letters
year: 2012

abstract: Resistive switching random access memory (RRAM) is widely considered as a disruptive technology. Despite tremendous efforts in theoretical modeling and physical analysis, details of how the conductive filament (CF) in metal oxide based filamentary RRAM devices is modified during normal device operations remain speculative, because direct experimental evidence at defect level has been missing. In this paper, a random telegraph signal based defect tracking technique (RDT) is developed for probing the location and movements of individual defects and their statistical spatial and energy characteristics in the CF of state of the art hafnium oxide RRAM devices. For the first time, the critical filament region of the CF is experimentally identified, which is located near, but not at, the bottom electrode with a length of nanometer scale. We demonstrate with the RDT technique that the modification of this key constriction region by defect movements can be observed and correlated with switching operation conditions, providing insight into the resistive switching mechanism.
author_names: Zheng Chai

Jigang Ma

Wei Dong Zhang

Bogdan Govoreanu

Jian Fu Zhang

Zhigang Ji

Malgorzata Jurczak
title: Probing the Critical Region of Conductive Filament in Nanoscale HfO2 Resistive Switching Device by Random Telegraph Signals
venue: IEEE Transactions on Electron Devices
year: 2017

abstract: The ultimate sensitivity of any solid state device is limited by fluctuations. Fluctuations are manifestations of the thermal motion of matter and the discreteness of its structure which are also inherent ingredients during the resistive switching process of resistance random access memory (RRAM) devices. In quest for the role of fluctuations in different memory states and to develop resistive switching based nonvolatile memory devices, here we present our study on random telegraph noise (RTN) resistance fluctuations in Cu doped Ge0.3Se0.7 based RRAM cells. The influence of temperature and electric field on the RTN fluctuations is studied on different resistance states of the memory cells to reveal the dynamics of the underlying fluctuators. Our analysis indicates that the observed fluctuations could arise from thermally activated transpositions of Cu ions inside ionic or redox "double site traps" triggering fluctuations in the current transport through a filamentary conducting path. Giant RTN fluctuation.
author_names: Rohit Soni

P M Meuffels

Adrian Petraru

Martin P Weides

Carsten Kugeler

Rainer Waser

Hermann Kohlstedt
title: Probing Cu doped Ge0.3Se0.7 based resistance switching memory devices with random telegraph noise
year: 2010

abstract: Nanoscale filament is the active area in oxygen vacancy type resistance random access memory (ReRAM) which is formed stochastically during electric test after being fabricated in a clean room. That is, the filament dimension cannot be controlled with a designed mask pattern. Here, we introduce a formula to describe the current cycle to cycle trajectories based on a stochastic differential equation (SDE) with microscopic structure parameters: filament dimension and oxygen vacancy concentration. Since ReRAM conduction follows hopping, the filament can be described by a random resistance network (RRN) The stochastic configuration of an RRN follows the Brownian motion, which is the key parameter in the diffusion of SDE. The formula provides a practically quantitative filament characterization method, which is verified by direct observation of the filament in actual devices. Based on the formula, we can predict ReRAM endurance with the given microscopic structure parameters.
author_names: Zhiqiang Wei

Koji Eriguchi
title: Analytic Modeling for Nanoscale Resistive Filament Variation in ReRAM With Stochastic Differential Equation
venue: IEEE Transactions on Electron Devices
year: 2017

abstract: The root cause of degradation and failure in nanoscale logic and memory devices originates from discrete defects (traps) that are created in the ultra thin dielectrics during fabrication (process induced) and or voltage and temperature stress (stress induced) In order to probe the chemistry of every discrete trap in terms of its bond state, charge state, physical location, region of influence, activation (relaxation) energy and trap depth below conduction band, low frequency noise (LFN) based measurement and analysis is a good approach as the random telegraph noise (RTN) signals which form the characteristic behavior of every trap undergoing stochastic carrier capture and emission process contain a wealth of information on the defect energetics. With nanodevices still undergoing aggressive device scaling, the presence of a finite number of discrete defects in logic and memory devices makes it easier to collect RTN signals and analyze them in detail. This study presents an overall perspective to current developments in RTN based studies on logic and memory devices and their impact on the variability in performance metrics. This is by no means an exhaustive overview; however, the key advancements in RTN as an effective defect spectroscopy tool are highlighted.
author_names: Nagarajan Raghavan

W H Liu

R Thamankar

Michel Bosman

Kin Leong Pey
title: Understanding defect kinetics in ultra thin dielectric logic and memory devices using random telegraph noise analysis
venue: 2015 IEEE 22nd International Symposium on the Physical and Failure Analysis of Integrated Circuits
year: 2015