CMOS-compatible wafer-scale Si subulate array for superb switching uniformity of RRAM with localized nanofilaments

Abstract

Resistive switching random access memory (RRAM) is one of the most promising candidates with highdensity three-dimensional integration characteristics for nextgeneration nonvolatile memory technology. However, the poor uniformity issue caused by the stochastic property of the conductive filament (CF) impedes the large-scale manufacture of RRAM chips. Subulate array has been introduced into the RRAM to minimize the CF randomness, but the methods are cumbersome, expensive, or resolution-limited for large-scale preparation. In this work, Si subulate array (SSA) substrates with different curvature radii prepared by a wafer-scale and nanoscale-controllable method are introduced for RRAM fabrication. The SSA structure, which induces a quasi-single CF or a few CFs formed in the tip region (TR) of the device as evidenced by the high-resolution transmission electron microscopy and energy dispersive spectroscopy characterization, dramatically improves the cycle-to-cycle and device-to-device uniformity. Decreasing the curvature radius of the TR significantly improves the device performance, including switching voltages, high/low resistance states, and retention characteristics. The improved uniformity can be attributed to the enhanced local electric field in the TR. The proposed SSA provides a low-cost, uniform, CMOS-compatible, and nanoscale-controllable optimization strategy for the largescale integration of highly uniform RRAM devices.

Advances of embedded resistive random access memory in industrial manufacturing and its potential applications

“…Furthermore, research efforts have focused on optimizing the algorithm design schemes for preparing embedded RRAM devices based on industrial CMOS technology, employing various peripheral circuit design approaches. These studies have investigated manufacturing properties such as energy efficiency, robustness, and RRAM process compatibility [155].…”

HfOx-Based Conductive Bridge Random Access Memory with Al2O3 Sandglass Nanostructures via Glancing Angle Deposition Technology toward Neuromorphic Applications

“…Zhang et al demonstrated Ag/ZrO 2 /Pt RRAM devices with a Si subulate array substrate; the CFs can be formed and confined in the tip region. 19 The devices show improving uniformity of the cycle-to-cycle and device-to-device variation. Au et al modulated the switching layer by embedding Ag nanoparticles into a BaTiO 3 thin film, for which Ag nanoparticles induced the formation of the CFs inside the switching layer, thus improving the RS behaviors with a lower operating voltage of less than 1 V. 20 Regarding CF channel design, Chen et al demonstrated a forming-free CBRAM device by regulating Cu CFs with a nanoporous carbon film fabricated by the magnetron sputtering process followed by a high-temperature annealing process in an inert atmosphere.…”

“…The enhanced electric fields can facilitate the ionization of Ag atoms so that CFs will predominantly nucleate and grow at the tip region. Zhang et al demonstrated Ag/ZrO 2 /Pt RRAM devices with a Si subulate array substrate; the CFs can be formed and confined in the tip region . The devices show improving uniformity of the cycle-to-cycle and device-to-device variation.…”