32 × 32 Crossbar Array Resistive Memory Composed of a Stacked Schottky Diode and Unipolar Resistive Memory

TLDR

The study fabricates and evaluates various 1‑diode/1‑resistor stacked crossbar array devices composed of a Schottky diode and a resistive switching memory cell. The Schottky diode, acting as a highly nonlinear resistor, controls the conducting path during switching and shields the memory element from noise during retention. The 1D1R crossbar array achieves a ~10³ resistance ratio, ~10⁵ rectification, sub‑50‑ns SET and ~600‑ns RESET times, and maintains stable endurance, retention, and reliable reading of an off‑state cell within a 32×32 array.

Abstract

Abstract Various array types of 1‐diode and 1‐resistor stacked crossbar array (1D1R CA) devices composed of a Schottky diode (SD) (Pt/TiO 2 /Ti/Pt) and a resistive switching (RS) memory cell (Pt/TiO 2 /Pt) are fabricated and their performances are investigated. The unit cell of the 1D1R CA device shows high RS resistance ratio (≈10 3 at 1.5 V) between low and high resistance state (LRS and HRS), and high rectification ratio (≈10 5 ) between LRS and reverse‐state SD. It also shows a short RS time of <50 ns for SET (resistance transition from HRS to LRS), and ≈600 ns for RESET (resistance transition from LRS to HRS), as well as stable RS endurance and data retention characteristics. It is experimentally confirmed that the selected unit cell in HRS (logically the “off” state) is stably readable when it is surrounded by unselected LRS (logically the “on” state) cells, in an array of up to 32 × 32 cells. The SD, as a highly non‐linear resistor, appropriately controls the conducting path formation during the switching and protects the memory element from the noise during retention.