Improved Pulse-Controlled Conductance Adjustment in Trilayer Resistors by Suppressing Current Overshoot.

Hojeong Ryu,Sungjun Kim

doi:10.3390/nano10122462

Abstract

In this work, we demonstrate the enhanced synaptic behaviors in trilayer dielectrics (HfO2/Si3N4/SiO2) on highly doped n-type silicon substrate. First, the three dielectric layers were subjected to material and chemical analyses and thoroughly investigated via transmission electron microscopy and X-ray photoelectron spectroscopy. The resistive switching and synaptic behaviors were improved by inserting a Si3N4 layer between the HfO2 and SiO2 layers. The electric field within SiO2 was mitigated, thus reducing the current overshoot in the trilayer device. The reset current was considerably reduced in the trilayer device compared to the bilayer device without a Si3N4 layer. Moreover, the nonlinear characteristics in the low-resistance state are helpful for implementing high-density memory. The higher array size in the trilayer device was verified by cross-point array simulation. Finally, the multiple conductance adjustment was demonstrated in the trilayer device by controlling the gradual set and reset switching behavior.

Highlights

Resistive switching memory is very attractive for a wide range of applications due to its various resistive switching characteristics stemming from a number of resistive switching materials by tunable resistive switching parameters such as on-resistance, off-resistance, and operation voltage [1,2,3,4,5]
Neuromorphic systems are specialized in data processing, such as complex pattern recognition
The conductance of the resistive switching memory cell placed on a cross-point array has multiple states and can be updated and controlled by the input pulse from the neuron circuit

Summary

Introduction

Resistive switching memory is very attractive for a wide range of applications due to its various resistive switching characteristics stemming from a number of resistive switching materials by tunable resistive switching parameters such as on-resistance, off-resistance, and operation voltage [1,2,3,4,5]. A tunnel barrier, such as SiO2 and Al2O3, with a large band gap, can enhance the resistive switching properties by reducing the operation current and increasing the nonlinearity of the I–V curve in the low-resistance state (LRS) [22,23]. The SiO2 layer can be formed when using silicon substrate as the bottom electrode and different methods such as native oxide, thermal oxide, and chemical vapor deposition (CVD) Another advantage of inserting the tunnel barrier with a high band gap is a reduction in the LRS current [21,22]. We demonstrated the improved synaptic behaviors by achieving gradual conductance control in the trilayer structure compared to the device without a Si3N4 layer

Materials and Methods

Set Forming