Approaches for Memristive Structures Using Scratching Probe Nanolithography: Towards Neuromorphic Applications

• Published in: Nanomaterials (Basel, Switzerland) Vol. 13; no. 10; p. 1583
• Main Authors: Tominov, Roman V, Vakulov, Zakhar E, Avilov, Vadim I, Shikhovtsov, Ivan A, Varganov, Vadim I, Kazantsev, Victor B, Gupta, Lovi Raj, Prakash, Chander, Smirnov, Vladimir A
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09-05-2023; MDPI
• Subjects: Analysis; Artificial intelligence; Atomic force microscopy; Diameters; Dielectric films; Grooves; Identification and classification; Lasers; memristor; Memristors; Morphology; Nanolithography; neuromorphic systems; Oxides; Photoresists; Pinholes; ReRAM; resistive switching; Scratching; scratching probe nanolithography; Software; Statistical analysis; Switching; Taguchi methods; Taguchi methods (Quality control); Thickness; Thin films; Variance analysis; Zinc oxide; Zinc oxides; Russia; United States > US; pulsed laser deposition; memristor; scratching probe nanolithography; ZnO thin films; ReRAM; neuromorphic systems; resistive switching; artificial intelligence; Taguchi method
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13101583

This paper proposes two different approaches to studying resistive switching of oxide thin films using scratching probe nanolithography of atomic force microscopy (AFM). These approaches allow us to assess the effects of memristor size and top-contact thickness on resistive switching. For that purpose, we investigated scratching probe nanolithography regimes using the Taguchi method, which is known as a reliable method for improving the reliability of the result. The AFM parameters, including normal load, scratch distance, probe speed, and probe direction, are optimized on the photoresist thin film by the Taguchi method. As a result, the pinholes with diameter ranged from 25.4 ± 2.2 nm to 85.1 ± 6.3 nm, and the groove array with a depth of 40.5 ± 3.7 nm and a roughness at the bottom of less than a few nanometers was formed. Then, based on the Si/TiN/ZnO/photoresist structures, we fabricated and investigated memristors with different spot sizes and TiN top contact thickness. As a result, the HRS/LRS ratio, U
, and I
are well controlled for a memristor size from 27 nm to 83 nm and ranged from ~8 to ~128, from 1.4 ± 0.1 V to 1.8 ± 0.2 V, and from (1.7 ± 0.2) × 10
A to (4.2 ± 0.6) × 10
A, respectively. Furthermore, the HRS/LRS ratio and U
are well controlled at a TiN top contact thickness from 8.3 ± 1.1 nm to 32.4 ± 4.2 nm and ranged from ~22 to ~188 and from 1.15 ± 0.05 V to 1.62 ± 0.06 V, respectively. The results can be used in the engineering and manufacturing of memristive structures for neuromorphic applications of brain-inspired artificial intelligence systems.