zch01-02二极管及其电路-20140922

模拟电子技术电子教案V1.0华中科技大学电信系邹韬平——半导体器件及其基本应用Ch01-02电子电路分析与设计2MicroelectronicsCircuitAnalysisandDesignChapter1SemiconductorMaterialsandDiodesChapter2DiodeCircuitsChapter3TheField-EffectTransistorChapter4BasicFETAmplifiersChapter5TheBipolarJunctionTransistorChapter6BasicBJTAmplifiersChapter7FrequencyResponseChapter8OutputStagesandPowerAmplifiers2Chapter9IdealOperationalAmplifiersandOp-AmpCircuits2Chapter10IntegratedCircuitBiasingandActiveLoads2Chapter11DifferentialandMultistageAmplifiers2Chapter12FeedbackandStability2Chapter13OperationalAmplifierCircuits2Chapter14NonidealEffectsinOperationalAmplifierCircuits2Chapter15ApplicationsandDesignofIntegratedCircuits(4h)(4h)(10h)基础、重点章较独立的分析任务(4h)(4h)(6h)(8h)(8h)(4h)(共52h)运放内部电路3二极管及其电路、分析Ch1.SemiconductorMaterialsandDiodes1.1SemiconductorMaterialsandProperties1.2ThePNJunction1.4DiodeCircuits-ACEquivalentCircuit1.3DiodeCircuits-DCAnalysisandModels1.5OtherDiodeTypesCh2.DiodeCircuits2.1RectifierCircuits2.2ZenerDiodeCircuits2.4Multiple-DiodeCircuits2.3ClipperandClamperCircuits2.5PhotodiodeandLEDCircuits问题1：二极管(PN结)主要特性是什么？其工程描述方法？问题2：二极管电路(非线性)的分析方法?最常用的是？问题3：常用的二极管电路及功能？41.1SemiconductorMaterialsandProperties1.1.1IntrinsicSemiconductors1.1.2ExtrinsicSemiconductors1.1.3DriftandDiffusionCurrents1.1.4ExcessCarriers+44价-原子结构简化模型Silicon(Si),germanium(Ge),galliumarsenideValenceelectronsSemiconductorMaterialsProperties(1)导电能力容易受环境因素影响（温度、光照等）(2)掺杂可以显著提高导电能力51.1.1IntrinsicSemiconductors本征半导体,纯半导体,无杂质半导体—single-crystalSiliconAtT=0K：allvalenceelectronsarebound;nochargeflowsinsulator1.1SemiconductorMaterialsandPropertiesFig1.2CovalentbondingstructureCovalentbondingValenceelectronCovalentband价带Conductionband导带ForbiddenBandgap禁带隙EgBandgapenergySi:Eg=1.1eV;Ge:Eg=0.66eV;Insulator:Eg=3~6eV;1eV=1.6×10-19J61.1.1IntrinsicSemiconductors1.1SemiconductorMaterialsandProperties+4+4+4+4+4+4+4+4+4本征激发GenerationFreeelectron温度光照GenerationFreeelectronValenceelectronGainenergy浓度导电能力Emptystate,positivecharge＋＋空位：带正电荷；靠相邻共价键中的价电子依次充填空位来实现电荷移动。取名为：Hole空穴可自由移动的正电荷；温度载流子浓度Carrier载流子:自由移动带电粒子复合electron-holerecombination－本征激发的逆过程见1.1.4ExcessCarriers71.1SemiconductorMaterialsandProperties1.1.1IntrinsicSemiconductors1.1.2ExtrinsicSemiconductors1.1.3DriftandDiffusionCurrents1.1.4ExcessCarriers+4原子结构简化模型Silicon(Si),germanium(Ge),galliumarsenideValenceelectronsSemiconductorMaterialsProperties(1)导电能力容易受环境因素影响（温度、光照等）(2)掺杂可以显著提高导电能力本征半导体、本征激发自由电子空穴复合81.1.2ExtrinsicSemiconductors1.N型半导体掺入少量的五价元素磷P2.P型半导体掺入少量的三价元素硼B自由电子是多数载流子（简称多子）空穴是少数载流子（简称少子）空穴是多数载流子自由电子为少数载流子。1.1SemiconductorMaterialsandProperties+4+4+4+4+4+4+4+5+4电子施主原子失去多余电子而形成正离子+4+4+4+4+4+4+4+3+4受主原子获得一个电子而形成一个负离子空穴空间电荷MajoritycarriersMinoritycarriersSpace-charge9掺入杂质对本征半导体的导电性有很大的影响，一些典型的数据如下:T=300K室温下,本征硅的电子和空穴浓度:ni=pi=1.5×1010/cm31本征硅的原子浓度:5×1022/cm33以上三个浓度基本上依次相差106/cm3。2掺杂后N型半导体中的自由电子浓度:n0Nd=1×1016/cm3,p0ni2/n0=2.25×104/cm3杂质对半导体导电性的影响101.1SemiconductorMaterialsandProperties1.1.1IntrinsicSemiconductors1.1.2ExtrinsicSemiconductors1.1.3DriftandDiffusionCurrents1.1.4ExcessCarriers+4原子结构简化模型Silicon(Si),germanium(Ge),galliumarsenideValenceelectronsSemiconductorMaterialsProperties(1)导电能力容易受环境因素影响（温度、光照等）(2)掺杂可以显著提高导电能力本征半导体、本征激发自由电子空穴复合N型半导体、施主杂质(5价)P型半导体、受主杂质(3价)•多数载流子、少数载流子111.1.3DriftandDiffusionCurrents1.1SemiconductorMaterialsandPropertiesDiffusion扩散运动—浓度差产生的载流子移动Drift漂移运动—在电场作用下，载流子的移动1.1.4ExcessCarriers扩散运动—浓度差产生的载流子移动载流子的注入12二极管及其电路、分析Ch1.SemiconductorMaterialsandDiodes1.1SemiconductorMaterialsandProperties1.2ThePNJunction1.4DiodeCircuits-ACEquivalentCircuit1.3DiodeCircuits-DCAnalysisandModels1.5OtherDiodeTypesCh2.DiodeCircuits2.1RectifierCircuits2.2ZenerDiodeCircuits2.4Multiple-DiodeCircuits2.3ClipperandClamperCircuits2.5PhotodiodeandLEDCircuits问题1：二极管(PN结)主要特性是什么？其工程描述方法？问题2：二极管电路(非线性)的分析方法?最常用的是？问题3：常用的二极管电路及功能？131.2ThePNJunction1.2.1TheEquilibriumpnJunctionObjective1.2.2Reverse-BiasedpnJunction1.2.3Forward-BiasedpnJunction1.2.4IdealCurrent-VoltageRelationship1.2.5pnJunctionDiodeTemperatureEffectBreakdownVoltageSwitchingTransient问题1：二极管(PN结)主要特性是什么？其工程描述方法？Drift&Diffusion14扩散漂移1.2.1TheEquilibriumpnJunction因为浓度差多子的扩散运动在P型半导体和N型半导体结合面，离子薄层形成的空间电荷区称为PN结。在空间电荷区中缺少多子，所以也称耗尽层。复合杂质离子形成空间电荷区空间电荷区形成内电场内电场促使少子漂移内电场阻止多子扩散是宽最后,多子的扩散和少子的漂移达到动态平衡。否问题？当动态平衡被外电场打破后，会如何？P-regionN-regionVbi-build-involtageSpace-chargeregionDepletionregion15PN结的单向导电性只有在外加电压时才…扩散与漂移的动态平衡将…定义：加正向电压，简称正偏加反向电压，简称反偏•扩散漂移•大的正向扩散电流（多子）•低电阻正向导通•漂移扩散•很小的反向漂移电流（少子）•高电阻反向截止1.2.2Reverse-BiasedpnJunction1.2.3Forward-BiasedpnJunction161.2.2Reverse-BiasedpnJunctionvRiRvR1.Depletionregionisincreased,highresistance.2.Majoritycarrierscannotcrossthejunction.3.MinoritycarrierssweepacrossPNeasily.But:IDFIDR,iR=IDR0EAEI4.JunctionCapacitanceDepletionLayerCapacitanceVRcharges(若f较高？)VaractorDiode用来描述势垒区的空间电荷随外加电压变化而变化的电容效应势垒电容CjSwitchingCharacteristics2101biRjjVVCCVbi-build-involtage17iDvD1.2.3Forward-BiasedpnJunctionSpace-chargeregion(Depletionregion)Built-inpotentialbarrier(Vbi)vDEAEIThermalequilibrium:(Vbi)Densitygradient22lnlnidaTidabinNNVnNNekTV