Ag掺杂TiO_(2)阻变特性的理论研究  

Theoretical study on the resistive switching characteristics of Ag doped TiO_(2)

作　　者：张燕[1] 申世英 颜安 栾加航 ZHAGN Yan;SHEN Shiying;YAN An;LUAN Jiahang(College of Engineering,Shandong Xiehe University,Jinan,Shandong 250107,China)

机构地区：[1]山东协和学院工学院,山东济南250107

出　　处：《石河子大学学报（自然科学版）》2024年第4期520-528,共9页Journal of Shihezi University(Natural Science)

基　　金：山东省高等学校青创科技支持计划项目(2023KJ294)。

摘　　要：阻变随机存储器(RRAM)是一种非易失性存储器。相比于传统的存储器,阻变随机存储器的读写速度和存储性能都实现了重大突破,是公认的新一代主流存储器。但是以TiO_(2)等金属氧化物为衬底的阻变随机存储器还存在阻变机制不清楚的问题。采用基于密度泛函理论的第一性原理,研究了Ag掺杂TiO_(2)的阻变特性,研究表明[001]、[110]、[011]、[111]四个方向的形成能和表面能均为负,最容易沉积形成表面。[011]、[111]方向最高势能面最大,电荷容易集聚,临界势能面同样最大,容易形成导电细丝。同时[011]、[111]方向的扩散势垒最小,容易形成导电通道。[011]和[111]方向的禁带宽度明显小于[001]和[110]方向,且存在明显的轨道杂化,容易在特定方向形成导电细丝。[011][111]两个方向上的电子和空穴有效质量约为[001][110]两个方向的2/3,而迁移率约为[001][110]方向的1.5~2倍,因此在外电场作用下更容易形成导电细丝。[011]和[111]方向电导率增长迅速,是实现阻变特性的理想方向。本文的研究结果可为改善以TiO_(2)为衬底的阻变随机存储器的性能提供理论指导。Resistive random access memory(RRAM)is a type of non-volatile memory.Compared to traditional memory,resistive random access memory has achieved significant breakthroughs in both read and write speed and storage performance,and is recognized as a new generation of mainstream memory.However,resistive random access memory based on metal oxides such as TiO_(2)still has unclear resistive mechanism.The first principles based on density functional theory were used to study the resistive switching characteristics of Ag doped TiO_(2),and the results revealed that the formation energy and surface energy in the four directions of[001],[110],[011],and[111]are all negative,making it the easiest to deposit and form a surface.The maximum potential energy surface value in the[011]and[111]direction is the largest,making it easy for charges to accumulate.The critical potential energy surface is also the largest,making it easy to form conductive filament.Simultaneously,the diffusion barrier in[011]and[111]direction is the minimum,making it easy to form conductive channels.The bandgap in the[011]and[111]directions is significantly smaller than that in the[001]and[110]directions,and there is a significant orbital hybridization,which makes it easy to form conductive filament in specific directions.The effective mass of electron and hole in[011][111]directions is about 2/3 of that in[001][110]directions,and the mobility is about 1.5-2 times that in the[001][110]direction,therefore,it is easier to form conductive filaments under the action of an external electric field.The conductivity increases rapidly in the[011]and[111]directions,which are ideal directions to achieve resistive switching characteristics.The research results can provide theoretical guidance for improving the performance of resistive random access memory based on TiO_(2).

关 键 词：阻变随机存储器 导电细丝 TiO_(2) 扩散势垒 第一性原理 

分 类 号：TN304.2[电子电信—物理电子学]