Polarization Characteristics and Resistive Switching Mechanism of Molybdenum Oxide Resistive Random Access Memory Devices

• Main Authors: CHEN, TZU-HSIANG, 陳子翔
• Other Authors: HSU, CHIH-CHIEH
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/bxjxjz

碩士 === 國立雲林科技大學 === 電子工程系 === 107 === In this thesis, the polarization characteristics of sol-gel MoO₃ semiconductors have been investigated. The dipoles in the bulk MoO₃ are turned to form a built-in electric field, which is opposite to the applied electric field. The I-V characteristic reveals that the negative differential resistance (NDR) effect occurs at -1.2 V in the negative bias region and about at 1 V in the positive bias region where the built-in electric field is equal to the applied electric field. However, the electrical characteristics obtained from different scanning directions are different due to the presence of built-in electric fields. The memory windows (R_HRS/R_LRS) of the device are approximately 10². Also, stability testing indicates that the memory can be repetitively operated over 5 x 10² cycles. The electrical characteristics of the MoO₃/ITO were measured using a tungsten probe contact along with a Keysight B1500A. The voltage cycles were applied to the tungsten contact, while the ITO electrode was grounded. The chemical structure and crystallinity of the MoO₃ thin film were characterized by X-ray photoelectron spectroscopy (XPS). The variation of the content of Mo⁶⁺ and Mo⁵⁺ in the bulk MoO₃ was analyzed. The crystallinity was investigated by X-ray diffraction (XRD), and it was found that the crystal structure of MoO₃ thin film changed from amorphous to the hexagonal structure after the annealing process. Field-emission scanning electron microscopy (FE-SEM) was used to observe the surface morphology and the thickness of the MoO₃ thin films. The analyses mentioned above can evidence the proposed resistive switching and carrier conduction mechanism of the MoO₃ RRAM.