Nanoporous Dielectric Resistive Memories Using Sequential Infiltration Synthesis

Abstract

Resistance switching in metal–insulator–metal structures has been extensively studied in recent years for use as synaptic elements for neuromorphic computing and as nonvolatile memory elements. However, high switching power requirements, device variabilities, and considerable trade-offs between low operating voltages, high on/off ratios, and low leakage have limited their utility. In this work, we have addressed these issues by demonstrating the use of ultraporous dielectrics as a pathway for high-performance resistive memory devices. Using a modified atomic layer deposition based technique known as sequential infiltration synthesis, which was developed originally for improving polymer properties such as enhanced etch resistance of electron-beam resists and for the creation of films for filtration and oleophilic applications, we are able to create ∼15 nm thick ultraporous (pore size ∼5 nm) oxide dielectrics with up to 73% porosity as the medium for filament formation. We show, using the Ag/Al2O3 system, that the ultraporous films result in ultrahigh on/off ratio (>109) at ultralow switching voltages (∼±600 mV) that are 10× smaller than those for the bulk case. In addition, the devices demonstrate fast switching, pulsed endurance up to 1 million cycles. and high temperature (125 °C) retention up to 104 s, making this approach highly promising for large-scale neuromorphic and memory applications. Additionally, this synthesis methodology provides a compatible, inexpensive route that is scalable and compatible with existing semiconductor nanofabrication methods and materials.

Reliable multilevel memristive neuromorphic devices based on amorphous matrix via quasi-1D filament confinement and buffer layer

“…S6). These are because the Ag ions preferentially migrate with the confinement effect via predefined pores rather than stochastic bulk diffusion, which is similar to the molecular dynamics of Ag diffusion in amorphous Al 2 O 3 with pores ( 25 ). To support our claim, we made a comparison about device performance with other nanopore-based CBRAMs including a variation of the devices in table S2.…”

“…These data implied that surface diffusion facilitated the migration of Ag ions through a 1D path rather than the bulk diffusion. In other words, the diffusivity of Ag along with the pores was enhanced compared to the bulk diffusivity (25,41,42). After the electroforming step, 90 dc sweeps were executed to compare the temporal variations of the devices.…”

“…In general, oxide-based RRAM can enhance reliability through localized switching, which reduces the uncontrollable 3D random filament growth and rupture process (12,22,23). Similarly, recent studies have shown the remarkable stability of CBRAM using confined filaments through various methods (4,(24)(25)(26). Previously, the 1D channel formation by using intrinsic dislocation of epitaxially grown SiGe on Si exhibited an exceptionally low variation, and it can be used as the confined pathway of CF to improve the CBRAM performance, which is known as epitaxial random access memory (epiRAM) (4).…”

Nanoscale Self-Assembly: Nanopatterning and Metrology

“…Recently, it has also been demonstrated that SIS represents an inexpensive and scalable strategy for the realization of resistive switching memories (ReRAM) that is compatible with existing semiconductor nanofabrication methods and materials. Indeed, Chakrabatarti et al [106] have shown that nanoporous AlO x grown by infiltration of PMMA acts as a dielectric layer for ReRAM cells characterized by a high on/off ratio (>10 9 ), low switching voltages (about 600 mV), retention up to 10 4 s and pulsed endurance up to 1 million cycles. These characteristics make these cells promising for memory and neuromorphic applications.…”

Al2O3 Dot and Antidot Array Synthesis in Hexagonally Packed Poly(styrene-block-methyl methacrylate) Nanometer-Thick Films for Nanostructure Fabrication

“…In particular, the growth of several oxides, like Al 2 O 3 , TiO 2 , 12 ZnO, 12 − 15 WO x , 16 VO x , 12 In 2 O 3 , 17 , 18 Ga 2 O 3 , 18 and SnO 2 , 19 has been already reported in the literature for different applications, such as high-resolution hard masks, 20 − 25 nanoparticle coatings and decoration, 8 , 26 , 27 superhydrophobic coatings, 28 optical materials and antireflection coatings, 29 , 30 enhancer of the contrast and scattering of nanostructures, 24 , 31 , 32 3D superlattices, 33 oil sorbents, 34 UV and thermal protection, 14 tuning of mechanical propertries, 35 sensing applications, 15 membranes, 36 − 38 elastic energy-storage structures, 39 electrical devices, 13 , 17 , 40 , 41 and resistive switching devices. 42 In addition, SIS can be also exploited as a postlithography technique to improve the extreme ultraviolet patterning process. 43 Waldman et al provided a systematic and comprehensive survey about current SIS results in the literature.…”