Statistical Fluctuations in HfO_x Resistive-Switching Memory: Part II—Random Telegraph Noise

Abstract

A key concern for resistive-switching random access memory (RRAM) is the read noise, due to the structural, chemical, and electrical modifications taking place at the localized current path, or conductive filament (CF). Read noise typically appears as a random telegraph noise (RTN), where the current randomly fluctuates between ON and OFF levels. This paper addresses RTN in RRAM, providing physical interpretations and models for the dependence on the programming and read conditions. First, we explain the RTN dependence on the compliance current during set transition in terms of the sizedependent depletion of carriers within the CF. Then, we discuss the bias dependence of the RTN switching times and amplitude, which can be explained by Joule heating and Poole-Frenkel barrier modifications arising from the electrostatics of the RTN fluctuating center.Index Terms-Noise fluctuations, random telegraph noise (RTN), resistive-switching random access memory (RRAM).

Statistical analysis of random telegraph noise in HfO2-based RRAM devices in LRS

“…1, reduce the readout margin of the device and may cause read failures. In this work we focus on the analysis of RTN in LRS, which has not been thoroughly investigated in the literature, compared to HRS [17,18]. Noise data are analyzed by considering also the physical parameters describing the device in LRS (i.e.…”

“…cycling variability and Random Telegraph Noise (RTN) [12][13][14][15][16], are hampering the device scaling and multi-bit storage implementation, delaying the full scale industrial exploitation of the RRAM concept. In this work we explore RTN characteristics in RRAM devices, focusing on the LRS, which has not been extensively covered in the literature as it exhibits lower current noise compared to the High Resistive State (HRS) [17,18]. Our previous works [13,14] exploited the color-coded time-lag plots and Hidden Markov Model [19] (HMM) to investigate the characteristics of RTN in RRAMs, showing that multi-level RTN can be seen as a superposition of many two-level RTN signals, each associated with a single trap [13].…”

Evolution of complementary resistive switching characteristics using IrOx/GdOx/Al2O3/TiN structure

“…1 A few reports have been investigated the CRS phenomena where two anti-serial RRAM cells are connected. [2][3][4] Yang et al 2 have reported the oxygen vacancy (V o ) depletion using Pd/Ta 2 O 5-x /TaO y /Pd structure. Gao et al 3 have used 4 nm-thick Ta layer in Pt/Ta 2 O 5 /Ta/Ta 2 O 5 /Pt stack.…”

“…Gao et al 3 have used 4 nm-thick Ta layer in Pt/Ta 2 O 5 /Ta/Ta 2 O 5 /Pt stack. Ambrogio et al 4 have reported the CRS characteristics using two anti-serially connected TiN/HfO 2 /TiN RRAM devices. Dai et al 5 have reported the Al/Ni/NiAlO x /Al 2 O 3-x /ITO structure.…”

New high resolution Random Telegraph Noise (RTN) characterization method for resistive RAM

“…Despite their excellent characteristics, RRAMs present some reliability problems, such as the occurrence of current fluctuations in the form of Random Telegraph Noise (RTN) [9][10][11][12][13]. RTN can be observed at both resistance states [14], although RTN is more relevant in the HRS because of the low current through the dielectric [15,16].…”