Amorphous ITZO-Based Selector Device for Memristor Crossbar Array

Abstract

In the era of digital transformation, a memristor and memristive circuit can provide an advanced computer architecture that efficiently processes a vast quantity of data. With the unique characteristic of memristor, a memristive crossbar array has been utilized for realization of nonvolatile memory, logic-in-memory circuit, and neuromorphic system. However, the crossbar array architecture suffers from leakage of current, known as the sneak current, which causes a cross-talk interference problem between adjacent memristor devices, leading to an unavoidable operational error and high power consumption. Here, we present an amorphous In-Sn-Zn-O (a-ITZO) oxide semiconductor-based selector device to address the sneak current issue. The a-ITZO-selector device is realized with the back-to-back Schottky diode with nonlinear current-voltage (I-V) characteristics. Its nonlinearity is dependent on the oxygen plasma treatment process which can suppress the surface electron accumulation layer arising on the a-ITZO surface. The a-ITZO-selector device shows reliable characteristics against electrical stress and high temperature. In addition, the selector device allows for a stable read margin over 1 Mbit of memristor crossbar array. The findings may offer a feasible solution for the development of a high-density memristor crossbar array.

The impact of oxygen vacancy defect density on the nonlinearity and short-term plasticity of TiO2-based exponential selector

“…A high nonlinearity of >10 4 was reported on TiO x [8][9][10][11], TaO x [5,12,13] and Co 3 O 4 -based [14] tunnelling selectors. Besides that, an amorphous ITZO-based selector was shown to achieve ∼900 nonlinearity in the V/3 scheme after oxygen plasma treatment [15]. An ultrathin three-monolayer MoS 2based tunnelling selector was also reported to achieve a low 25 nonlinearity value [16].…”

Gradual conductance modulation by defect reorganization in amorphous oxide memristors

“…[30][31][32][33] Recently, all-optical modulated synaptic behavior in a-IGZO devices has also been reported. 34 Other amorphous oxides also exhibit promising memristive properties, such as ZnSnO-based amorphous oxides, [35][36][37][38][39] a-SrVO x , 40 a-InWZnO, 41 a-InSnZnO, 42 etc. However, it is complicated to derive a detailed mechanistic picture of memristive properties.…”