Self-Rectifying Resistive Switching and Short-Term Memory Characteristics in Pt/HfO2/TaOx/TiN Artificial Synaptic Device.

Hojeong Ryu,Sungjun Kim

doi:10.3390/nano10112159

Abstract

Here, we propose a Pt/HfO2/TaOx/TiN artificial synaptic device that is an excellent candidate for artificial synapses. First, XPS analysis is conducted to provide the dielectric (HfO2/TaOx/TiN) information deposited by DC sputtering and atomic layer deposition (ALD). The self-rectifying resistive switching characteristics are achieved by the asymmetric device stack, which is an advantage of the current suppression in the crossbar array structure. The results show that the programmed data are lost over time and that the decay rate, which is verified from the retention test, can be adjusted by controlling the compliance current (CC). Based on these properties, we emulate bio-synaptic characteristics, such as short-term plasticity (STP), long-term plasticity (LTP), and paired-pulse facilitation (PPF), in the self-rectifying I–V characteristics of the Pt/HfO2/TaOx/TiN bilayer memristor device. The PPF characteristics are mimicked by replacing the bio-stimulation with the interval time of paired pulse inputs. The typical potentiation and depression are also implemented by optimizing the set and reset pulse. Finally, we demonstrate the natural depression by varying the interval time between pulse inputs.

Highlights

Resistive random-access memory (RRAM) based on various metal oxides has been extensively studied due to its superior non-volatile memory performance, in terms of its high endurance, low-power operation, high speed switching, and good complementary metal-oxide-semiconductor (CMOS) compatibility [1,2,3,4,5,6,7,8,9,10]
The cross-point arrangement of memory cells allows for RRAM and phase change random-access memory (PRAM) [13] to be more highly integrated than other emerging memory devices such as magnetic random-access memory (MRAM) [14] and ferroelectric random-access memory (FRAM) [15]
The results prove that the Pt/HfO2/TaOx/TiN memristor device has self-rectifying resistive switching I–V characteristics

Summary

Introduction

Resistive random-access memory (RRAM) based on various metal oxides has been extensively studied due to its superior non-volatile memory performance, in terms of its high endurance, low-power operation, high speed switching, and good complementary metal-oxide-semiconductor (CMOS) compatibility [1,2,3,4,5,6,7,8,9,10]. Metal oxides, such as TaOx and HfOx, have better reproducibility and variability than other material systems like organic [11] and 2D materials [12]. Leakage current flows through the unselected cells in a low resistance state (LRS) when accessing the data on the target memory cell

Methods

Results

Conclusion