Multi-Level Resistive Switching of Pt/HfO2/TaN Memory Device

Hojeong Ryu,Sungjun Kim,Hoeje Jung,Kisong Lee

doi:10.3390/met11121885

Abstract

This work characterizes resistive switching and neuromorphic simulation of Pt/HfO2/TaN stack as an artificial synaptic device. A stable bipolar resistive switching operation is performed by repetitive DC sweep cycles. Furthermore, endurance (DC 100 cycles) and retention (5000 s) are demonstrated for reliable resistive operation. Low-resistance and high-resistance states follow the Ohmic conduction and Poole–Frenkel emission, respectively, which is verified through the fitting process. For practical operation, the set and reset processes are performed through pulses. Further, potentiation and depression are demonstrated for neuromorphic application. Finally, neuromorphic system simulation is performed through a neural network for pattern recognition accuracy of the Fashion Modified National Institute of Standards and Technology dataset.

Highlights

Unipolar is commonly found in the dielectrics of NiO, HfO2, and TiO2, in which the set and reset processes occur in the same polarity [36,37,38]
The set and reset processes of the bipolar type occur at different polarities, and switching is reported in many materials, such as metal oxides, metal nitrides, 2D materials, and organic materials [1,2]
In the case of an MIM Resistive switching random access memory (RRAM) composed of non-diffusion type metals such as TiN and TaN and a metal oxide such as HfO2, TaOx, and Al2O3, the resistance value can be reversibly changed by the change in the oxygen vacancies inside the dielectric [44,45]

Summary

Introduction

Resistive switching random access memory (RRAM) has attracted considerable attention in various applications such as storage memory [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16], processing-in-memory (PIM) [17,18,19,20], and neuromorphic systems [21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. Unipolar is commonly found in the dielectrics of NiO, HfO2, and TiO2, in which the set and reset processes occur in the same polarity [36,37,38].

Results

Conclusion