Highly flexible resistive switching memory based on amorphous-nanocrystalline hafnium oxide films

Self Cite

Mechanical flexibility and electrical reliability establish the fundamental criteria for wearable and implantable electronic devices. In order to receive intrinsically stretchable resistive switching memories, both the electrode and storage media should be flexible yet retain stable electrical properties. Experimental results and finite element analysis reveal that the formation of 3D liquid metal galinstan (GaInSn) calabash bunch conductive network in poly(dimethyl siloxane) (PDMS) matrix allows GaInSn@PDMS composite as soft electrode with the stable conductivity of >1.3 × 103 S cm−1 at the stretching strains of >80% and a fracture strain extreme of 108.14%, while the third‐generation metal–organic framework MIL‐53 thin film with a facial rhombohedral topology enables large mechanical deformation up to a theoretical level of 17.7%. Combining the use of liquid metal–based electrode and MIL‐53 switching layer, for the first time, intrinsically stretchable RRAM device Ag/MIL‐53/GaInSn@PDMS is demonstrated that can exhibit reliable resistive switching characteristics at the strain level of 10%. The formation of fluidic gallium conductive filaments, together with the structural flexibility of the GaInSn@PDMS soft electrode and MIL‐53 insulating layer, accounts for the uniform resistive switching under stretching deformation scenario.

Section: Introductionmentioning

confidence: 99%

Intrinsically Stretchable Resistive Switching Memory Enabled by Combining a Liquid Metal–Based Soft Electrode and a Metal–Organic Framework Insulator

Niu

et al. 2018

Self Cite

“…[1][2][3] Nonvolatile resistive random access memories (RRAM) have simple structure, excellent scalability, high switching speed, good retention, and low power consumption. [1][2][3] Nonvolatile resistive random access memories (RRAM) have simple structure, excellent scalability, high switching speed, good retention, and low power consumption.…”

mentioning

confidence: 99%

Role of Oxygen Vacancies at the TiO₂/HfO₂ Interface in Flexible Oxide‐Based Resistive Switching Memory

Zhang

Huang

Xia

et al. 2019

116

important role in flexible electronics. [1][2][3] Nonvolatile resistive random access memories (RRAM) have simple structure, excellent scalability, high switching speed, good retention, and low power consumption. Thus, they have been considered as promising candidates for charge-based memory and Flash. [4,5] In terms of flexible RRAM (FRRAM) applications, the investigations mainly focus on device processing, resistive switching (RS) behaviors, and mechanical flexibilities. [6][7][8] Many efforts have been devoted to achieve high performance FRRAMs with both small RS parameters variation and excellent flexibility. One of the representative obstacles is the nonuniformity of RS parameters, which leads to false programming and gives rise to readout hazards. [9,10] Some FRRAMs demonstrated fast programming speed, large storage window, excellent flexibility, and mechanical endurance. However, the coefficients of variation for the RS parameters were unexpectedly high. [10] On the basis of conducting filament (CF) theory in RRAM devices, the switching mechanism is highly depended on the CF formation/disruption during the writing/programming process, which in turn affects the device performance. As concerned as the valence change memory (VCM) RRAM, oxygen vacancies play an important role in a redox reaction, which determines the filament morphology. In order to enhance the performance and improve the distribution of switching parameters, bilayer RS structure such as /indium tin oxide (ITO), is proposed. Such RS layer can control the formation/rupture of CF consisting of oxygen vacancies. [11][12][13] HfO 2 and TiO 2 are typical high dielectric constant transition metal oxides in complementary metal oxide semiconductor (CMOS) integrated circuit applications. Due to the simple compositions and good compatibilities with CMOS processing, they have been widely investigated for memory device applications. [14] Especially, HfO 2 /TiO 2 bilayer structure has exhibited desired features, including self-rectification, multiple resistance states, self compliance, and stable bipolar RS property. [14,15] Bilayer structure based RRAM can operate at low voltage, which decreases the heat accumulation in the operating process and reduces the power consumption. [16] Thus, it is speculated that the stability of bilayer HfO 2 /TiO 2 FRRAM device will be improved by avoiding the undesirable heating during the read/write process. The low energy consumptions and high stabilities are highly desirable for wearable electronic applications.The authors declare no conflict of interest. Figure 6. a) The 1000th, 1500th, and 2000th I-V curves taken on FRRAM device. b) I-V curves at different stop voltages ranged between −1.3 and −1.6 V with step of 0.1 V.www.advancedsciencenews.com

“…EDS is semiquantitation analysis, it still showed the significantly different composition to depict the tendency of elements. [25,26] Therefore, HfO 2 played an important role in developing ReRAM devices based on nanowires. NiO region with CFs was fifteen times higher than NiO region without CFs, which indicated that conductive filament was hafniumdominant path.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…[6][7][8][9] The resistive switching behavior in ReRAM devices is generally understood as the reversible formation and disruption of conducting filaments (CFs). Hence, a variety of materials for the insulator layer, such as Ta 2 O 5 , [13] NiO, [14,15] CuO, [16] TiO 2 , [17][18][19][20] Al 2 O 3 , [21,22] ZnO, [11] and HfO x , [23][24][25][26] have been studied to show their resistive switching behavior. [10] CFs are commonly categorized according to their formation types, including electrochemical metallization [5,11,12] and valence change mechanism.…”

mentioning

confidence: 99%

“…The scanning electron microscopy (SEM) images show that there were two different types of the fractured nanowires, as illustrated in Figure S3 of the Supporting Information. According to previous research, [23][24][25][26] HfO 2 had excellent properties as a switching layer of ReRAM devices, so we selected it to modify the characteristics of the Ni/NiO nanowire ReRAM devices. From the SEM images, two fracture types occurred close to the middle of the nanowires due to insufficient heat dissipation.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Ni/NiO/HfO₂ Core/Multishell Nanowire ReRAM Devices with Excellent Resistive Switching Properties

Huang

Chen

Ting

et al. 2018

magnetic random-access memory, [3] ferroelectric random-access memory, [4] and resistive random-access memory (ReRAM). [5] Among them, ReRAM is one of the most powerful candidates due to its higher endurance, higher retention, faster write and read speeds, and lower power consumption. In addition, it has a simple sandwich structure of metal-insulator-metal (MIM) for data storage and information compilation. [6][7][8][9] The resistive switching behavior in ReRAM devices is generally understood as the reversible formation and disruption of conducting filaments (CFs). In addition, the SET process was defined as the resistance switching from the high-resistance state (HRS) to the low-resistance state (LRS); by contrast, the RESET process operates inversely. [10] CFs are commonly categorized according to their formation types, including electrochemical metallization [5,11,12] and valence change mechanism. When the top electrode is the active metal (such as Ag or Cu), the metal would be oxidized to anionic specie and then diffuse into the insulator layer due to the external electric field. The anions in the insulator layer would accept electrons, resulting in a reduction process to form CFs. On the other hand, when the top electrode is the inert metal (such as Au or Pt), the oxygen ions would migrate toward high electric potential and form oxygen vacancies in the insulator layer. The oxygen vacancies would connect the electrodes, causing resistive switching from the HRS to LRS. Moreover, the insulator layer plays an essential role in ReRAM devices and has significantly influence on ReRAM performance. Hence, a variety of materials for the insulator layer, such as Ta 2 O 5 , [13] NiO, [14,15] CuO, [16] TiO 2 , [17][18][19][20] Al 2 O 3 , [21,22] ZnO, [11] and HfO x , [23][24][25][26] have been studied to show their resistive switching behavior. To overcome the problem of scaling down, 1D nanowires have been applied to ReRAM fabrication. However, the endurance and reliability of nanowire devices are still not sufficient for commercial production. Although many kinds of nanowires have been widely discussed, core/shell nanowires provide a strategy to reach nanoscale MIM structure and have exhibited high potential for applications in ultrahigh density ReRAM devices because the switching behavior could be controlled within the few-nanometer shell. [7,8,15,27,28] More research about performance enhancement and the switching mechanism are still needed. Owing to the excellent resistive switching characteristics in HfO 2 -based Resistive random-access memory (ReRAM) is one of the most promising types of nonvolatile memory because it has several important advantages, for example, a simple metal-insulator-metal structure, fast operating speed, high endurance, high retention, and low energy consumption. However, the reliability of ReRAM nanodevices is not persistent, and the complete switching mechanism is not fully understood. In this study, a unique 1D Ni/NiO/HfO 2 core/multishell ReRAM nanodevice is designed and fabricated. The d...