Observation of Resistive Switching Memory by Reducing Device Size in a New Cr/CrO x /TiO x /TiN Structure.

Debanjan Jana,Subhranu Samanta,Sourav Roy,Siddheswar Maikap,Yu Feng Lin

doi:10.1007/s40820-015-0055-3

Abstract

The resistive switching memory characteristics of 100 randomly measured devices were observed by reducing device size in a Cr/CrOx/TiOx/TiN structure for the first time. Transmission electron microscope image confirmed a via-hole size of 0.4 µm. A 3-nm-thick amorphous TiOx with 4-nm-thick polycrystalline CrOx layer was observed. A small 0.4-µm device shows reversible resistive switching at a current compliance of 300 µA as compared to other larger size devices (1–8 µm) owing to reduction of leakage current through the TiOx layer. Good device-to-device uniformity with a yield of >85 % has been clarified by weibull distribution owing to higher slope/shape factor. The switching mechanism is based on oxygen vacancy migration from the CrOx layer and filament formation/rupture in the TiOx layer. Long read pulse endurance of >105 cycles, good data retention of 6 h, and a program/erase speed of 1 µs pulse width have been obtained.

Highlights

Resistive random access memory (RRAM) has been investigated for the next-generation non-volatile memory applications [1, 2]
Observation of resistive switching memory by reducing device size as well as leakage current has been revealed in a new Cr/CrOx/TiOx/TiN resistive random access memory (RRAM) device
By measuring 100 random devices it is found that a smaller size device has lower leakage current and resistive switching characteristics are observed

Summary

Introduction

Resistive random access memory (RRAM) has been investigated for the next-generation non-volatile memory applications [1, 2]. Various materials like HfOx [4], TaOx [5, 6], TiOx [7,8,9,10], and so on have been reported by many groups. Many groups have reported these TiOx-based different RRAM devices, resistive switching characteristics by reducing device size as well as leakage current in a Cr/CrOx/TiOx/TiN structure have not been investigated yet. To obtain good resistive switching characteristics, both amorphous TiOx switching and polycrystalline CrOx oxygen vacancy supply layers are effectively combined with smaller device sizes. Long read pulse endurance of [105 cycles, stable data retention of [6 h, and good program/erase (P/E) endurance with a pulse width of 1 ls are obtained, which indicate future application of this new Cr/CrOx/TiOx/TiN resistive switching memory device

Experimental

Cr CrO x TiO x 2 TiN 3

Conclusions