应力与本征缺陷影响硅晶体电学性质机理第一性原理研究

本科学生毕业论文2013年5月10日论文题目：应力与本征缺陷影响硅晶体电学性质机理第一性原理研究学院：电子工程学院年级：2009级专业：电子科学与技术（微电子）姓名：李册学号：20096647指导教师：李青坤I摘要如今对于半导体材料硅的研究已经日渐成熟，硅已经是最广泛应用的一类半导体，在微电子和集成电路行业中硅占据着主导地位，通常通过掺杂杂质来改变硅的导电性能，硅的掺杂技术已经被普遍应用并且越来越成熟，并制成各种器件。然而在应力和本征缺陷对硅的电学性质的作用却很少提及。在对半导体材料的研究和学习中可知，缺陷的电学特性对半导体也有着一定的影响，参杂原子可以提供载流子提高其导电特性，而空位等缺陷在禁带中产生深能级，因此缺陷影响着半导体的禁带宽度和载流子数目。因此缺陷对硅的导电特性起着至关重要的作用。当对硅晶体某一晶向上施加一个拉伸或压缩的应力时会对硅结构造成一定的影响，导致禁带宽度会发生变化，使其导电性能也发生变化。本文所进行的工作就是研究应力和本征缺陷双重因素作用下影响硅电学性质机理的第一性原理的研究。利用MaterialsStudio6.0软件来计算分别对硅的111和100晶向施加拉伸和压缩的应力其电学性质变化并绘制应力随应变曲线，并且绘制出能带图、态密度图、分波态密度图，进一步解释其应力和本征缺陷对硅导电性质机理的影响。从而寻找不依赖掺杂而只利用本征缺陷和应力来调控硅的电学性质的方法。利用应力和本征缺陷调节硅的禁带宽度改变半导体的性能并通过能带图、分波态密度图、态密度图进行理论分析其机理。并解释应力和本征缺陷作用下硅晶体宏观现象的微观本原，并为硅工业发展提供理论支持。关键词第一性原理；硅；本征缺陷；应力IIAbstractNowforthestudyofsemiconductorsiliconismoreandmoremature,siliconisthemostwidelyusedakindofsemiconductor.Siliconinmicroelectronicsandintegratedcircuitindustryoccupyadominantposition.Typicallybydopingtheimpuritytochangetheconductivityofthesilicon,thesilicondopingtechniquehasbeenwidelyappliedandthemoremature.Andmakeintoavarietyofdevices.Buttheroleofstressandintrinsicdefectsintheelectricalpropertiesofsiliconisrarelymentioned.Asknowninthesemiconductormaterialsresearchandstudy,theelectricalpropertiesofdefectshasacertainimpactonthesemiconductor,impurityatommayprovidethecarriertoimproveitsconductivecharacteristics.Whilevacanciesandotherdefectsintheformationofdeeplevelsinthebandgap,defectaffectingthebandgapofthesemiconductorandthenumberofcarriers.Therefore,defectintheelectricalpropertiesofsiliconplaysavitalrole.Whenappliedatensileorcompressivestressonaparticularcrystalorientationofthesiliconandcrystalsiliconstructureshavebeenaffected.Bandgapwillchangealsoitsconductiveproperties.TheworkofthispaperistostudystressandintrinsicdefectsinthedualroleofthefactorsaffectingthemechanismofsiliconelectricalpropertiesinFirstprinciples.UsingMaterialsStudio6.0softwaretocalculatethesilicon111and110crystalorientationappliedtensileandcompressivestresschangesitselectricalpropertiesanddrawingstresswithstraincurve.Anddrawtheenergybanddiagram,densityofstates,partialdensityofstatesmap,Furtherexplainedthatthestressandtheintrinsicdefectsinthemechanismofthenatureoftheconductivesilicon.Inordertofindtheelectricalpropertiesofthemethoddoesnotdependonlyadvantageoftheintrinsicdefectsandstressregulationsilicon-doped.Theuseofstressandtheintrinsicdefectsadjustthebandgapofsiliconandchangetheperformanceofthesemiconductorandthroughtheenergybanddiagram,partialdensityofstatesmap,densityofstatestheoreticalanalysisofitsmechanism.Andexplainthestressandintrinsicdefectsundertheactionofsiliconcrystalsofthephenomenonofmicro-primitiveandprovidetheoreticalsupportforthesiliconindustrydevelopment.IIIKeywordsFirstprinciple;silicon;intrinsicdefect;stress目录摘要............................................................................................................................................IAbstract...................................................................................................................................II第一章绪论.............................................................................................................................11.1半导体硅的应用........................................................................................................11.2半导体中的缺陷结构及其影响................................................................................11.2.1缺陷种类.........................................................................................................11.2.2点缺陷中的主要类型介绍.............................................................................21.2.3本征缺陷对晶体的导电性质影响.................................................................21.3力学对硅的电学性质的影响....................................................................................31.3.1应力与应变.....................................................................................................31.3.2应力对硅电学性质产生影响.........................................................................31.4本文主要工作内容....................................................................................................3第二章第一性原理简介.........................................................................................................52.1第一性原理算法........................................................................................................52.1.1局部密度近似方法.........................................................................................52.1.2广义梯度近似法.............................................................................................62.2第一性原理分析材料微观相互作用的基本方法....................................................62.2.1能带图.............................................................................................................62.2.2态密度图.........................................................................................................62.2.3分波态密度.....................................................................................................72.3第一性原理计算软件介绍..............................