Characterization of low-frequency noise in the resistive switching of transition metal oxide HfO2

Abstract

-Low frequency noise measurements were performed on HfO 2 based bipolar resistive switching memory devices. A 1/f α DC noise power spectral density was observed with α~1 for low resistance state and α~2 for high resistance state. We developed an electron tunneling model to elucidate the conduction process which showed that the 1/f α behavior was due to the distribution of relaxation times of electron tunneling between the electrodes and the traps in the conducting filaments. The transition of the slope index α from 1 to 2 at a certain cutoff frequency indicates that there is a tunneling gap formed between electrodes and the residual of the conductive filaments in the high resistance state.Keywords -low frequency noise, resistive switching (RRAM), transition metal oxide, electron tunneling Currently, transition metal oxide based resistive switching memory is extensively studied as one of the most competitive candidates for future non-volatile memory applications due to its simple structure, fast switching speed, great scalability, and compatibility with silicon complementary metal-oxidesemiconductor (CMOS) technology [9][10][11]. The mechanism of resistive switching phenomenon in oxides is usually attributed to the formation/rupture of conductive filaments (CFs) which may consist of oxygen vacancies or metal precipitates [12]. The set process from high resistance state (HRS) to low resistance state (LRS) is interpreted as a dielectric soft breakdown associated with the migration of oxygen ions toward the anode, leaving behind the oxygen vacancies in the bulk oxide to form CFs connecting both electrodes [13]. To reset from LRS to HRS, there are two modes: in the unipolar reset (the reset occurs at the same polarity as the set), Joule-heating-assisted diffusion of oxygen ions from anode and surrounding oxides rupture the CFs by recombination with oxygen vacancies or re-oxidization of the metal precipitates [14]. In the bipolar reset (the reset occurs at the opposite polarity as the set), electric-field-assisted drift of oxygen ions from the oxygen reservoir rupture the CFs [15]. In the bipolar switching mode, oxidizable electrode materials such as Ti, TiN, TaN are usually used to serve as the oxygen reservoir providing the oxygen ions during the reset process [16]. The device used in this paper exhibits the bipolar switching mode. Although such a phenomenological physical switching picture above has been proposed, the detailed characterization and quantitative theoretical analysis of the conduction mechanism is still lacking in the literature.Low frequency noise (LFN) measurement is a technique that can electrically characterize the trapassisted conduction process in dielectrics [17][18][19] NiO [22] (in this paper f refers to the frequency). In this work, we perform LFN measurement on HfO 2 based resistive switching memory to investigate its conduction and switching mechanism. HfO 2 is chosen because HfO 2 based devices exhibit desirable properties such as ultra-fast switching speed (<ns), excellent s...

Conduction in alumina with atomic scale copper filaments

“…The resistive memory devices have a potential for longer endurance, faster response, and lower energy consumption compared with non-volatile Flash memory. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] A number of experimental studies use alumina in resistive switching. [22][23][24][25][26][27][28][29][30][31][32] Alumina is a desirable material because it has a large band gap and as a result the leakage current is small.…”

Effect of Hydrogen on Long-Term Reliability of InZnO TFTs Characterized by Low-Frequency Noise

“…Thence, the carrier concentration in the channel of IZO TFTs is increased, resulting in the growth of μFE. The LFN properties can electrically characterize the trap-assisted conduction process in channels and gate dielectrics in TFTs [17]. To investigate the affect of the hydrogen stress on the LFN characteristics of devices, the normalized drain current noise (SID/ID 2 ) versus drain current (ID) was obtained before and after the hydrogen stress.…”

Low-Frequency 1/f Noise Characteristics of Ultra-Thin AlOx-Based Resistive Switching Memory Devices with Magneto-Resistive Responses

“…It has been reported that the nearly stoichiometric Al 2 O 3 layer could act as a diffusion barrier for oxygen ions, whereas the oxygen-deficient AlO x layer displays characteristics of charge trapping/de-trapping properties similar to perovskite-type complex oxides [19,20]. The low-frequency noise (LFN) measurement has been widely applied to characterize various disordered systems, which could provide deep insights into the inherent charge transport dynamics related to charge trapping/de-trapping phenomena with randomly distributed trap sites [21,22]. Here, we report an extensive study on the 1/f LFN characteristics of the AlO x -based RS memory devices to address the charge transport dynamics by analyzing the noise power spectrum density (PSD) through Hooge's empirical model [23,24].…”