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Title: Characteristics and mechanism study of cerium oxide based random access memories

Abstract

In this work, low operating voltage and high resistance ratio of different resistance states of binary transition metal oxide based resistive random access memories (RRAMs) are demonstrated. Binary transition metal oxides with high dielectric constant have been explored for RRAM application for years. However, CeO{sub x} is considered as a relatively new material to other dielectrics. Since research on CeO{sub x} based RRAM is still at preliminary stage, fundamental characteristics of RRAM such as scalability and mechanism studies need to be done before moving further. Here, we show very high operation window and low switching voltage of CeO{sub x} RRAMs and also compare electrical performance of Al/CeO{sub x}/Au system between different thin film deposition methods and discuss characteristics and resistive switching mechanism.

Authors:
; ; ; ;  [1]
  1. Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd. Bldg. 160, Austin, Texas 78758 (United States)
Publication Date:
OSTI Identifier:
22398975
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM; CERIUM OXIDES; COMPARATIVE EVALUATIONS; DEPOSITION; DIELECTRIC MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; GOLD; HETEROJUNCTIONS; OPERATION; PERFORMANCE; PERMITTIVITY; RANDOMNESS; THIN FILMS

Citation Formats

Hsieh, Cheng-Chih, Roy, Anupam, Rai, Amritesh, Chang, Yao-Feng, and Banerjee, Sanjay K. Characteristics and mechanism study of cerium oxide based random access memories. United States: N. p., 2015. Web. doi:10.1063/1.4919442.
Hsieh, Cheng-Chih, Roy, Anupam, Rai, Amritesh, Chang, Yao-Feng, & Banerjee, Sanjay K. Characteristics and mechanism study of cerium oxide based random access memories. United States. doi:10.1063/1.4919442.
Hsieh, Cheng-Chih, Roy, Anupam, Rai, Amritesh, Chang, Yao-Feng, and Banerjee, Sanjay K. Mon . "Characteristics and mechanism study of cerium oxide based random access memories". United States. doi:10.1063/1.4919442.
@article{osti_22398975,
title = {Characteristics and mechanism study of cerium oxide based random access memories},
author = {Hsieh, Cheng-Chih and Roy, Anupam and Rai, Amritesh and Chang, Yao-Feng and Banerjee, Sanjay K.},
abstractNote = {In this work, low operating voltage and high resistance ratio of different resistance states of binary transition metal oxide based resistive random access memories (RRAMs) are demonstrated. Binary transition metal oxides with high dielectric constant have been explored for RRAM application for years. However, CeO{sub x} is considered as a relatively new material to other dielectrics. Since research on CeO{sub x} based RRAM is still at preliminary stage, fundamental characteristics of RRAM such as scalability and mechanism studies need to be done before moving further. Here, we show very high operation window and low switching voltage of CeO{sub x} RRAMs and also compare electrical performance of Al/CeO{sub x}/Au system between different thin film deposition methods and discuss characteristics and resistive switching mechanism.},
doi = {10.1063/1.4919442},
journal = {Applied Physics Letters},
number = 17,
volume = 106,
place = {United States},
year = {Mon Apr 27 00:00:00 EDT 2015},
month = {Mon Apr 27 00:00:00 EDT 2015}
}
  • The energies of atomic processes in resistive random access memories (RRAMs) are calculated for four typical oxides, HfO{sub 2}, TiO{sub 2}, Ta{sub 2}O{sub 5}, and Al{sub 2}O{sub 3}, to define a materials selection process. O vacancies have the lowest defect formation energy in the O-poor limit and dominate the processes. A band diagram defines the operating Fermi energy and O chemical potential range. It is shown how the scavenger metal can be used to vary the O vacancy formation energy, via controlling the O chemical potential, and the mean Fermi energy. The high endurance of Ta{sub 2}O{sub 5} RRAM ismore » related to its more stable amorphous phase and the adaptive lattice rearrangements of its O vacancy.« less
  • The authors report an improvement in resistive switching (RS) characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO)-based resistive random access memory devices using hydrogen post-annealing. Because this a-IGZO thin film has oxygen off-stoichiometry in the form of deficient and excessive oxygen sites, the film properties can be improved by introducing hydrogen atoms through the annealing process. After hydrogen post-annealing, the device exhibited a stable bipolar RS, low-voltage set and reset operation, long retention (>10{sup 5 }s), good endurance (>10{sup 6} cycles), and a narrow distribution in each current state. The effect of hydrogen post-annealing is also investigated by analyzing the sample surface using X-raymore » photon spectroscopy and atomic force microscopy.« less
  • In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.
  • The metal nanocrystals (NCs) embedded-NiN-based resistive random access memory cells are demonstrated using several metal NCs (i.e., Pt, Ni, and Ti) with different physical parameters in order to investigate the metal NC's dependence on resistive switching (RS) characteristics. First, depending on the electronegativity of metal, the size of metal NCs is determined and this affects the operating current of memory cells. If metal NCs with high electronegativity are incorporated, the size of the NCs is reduced; hence, the operating current is reduced owing to the reduced density of the electric field around the metal NCs. Second, the potential wells aremore » formed by the difference of work function between the metal NCs and active layer, and the barrier height of the potential wells affects the level of operating voltage as well as the conduction mechanism of metal NCs embedded memory cells. Therefore, by understanding these correlations between the active layer and embedded metal NCs, we can optimize the RS properties of metal NCs embedded memory cells as well as predict their conduction mechanisms.« less