部分习题解答部分物理常数:191412S103Gi1412S133Gi1.610C,0.026V(300k),(Si)11.88.854101.04510Fcm,(Si)1.09eV,(Si)1.510cm,(Ge)168.854101.41710Fcm,(Ge)0.66eV,(Ge)2.410cm,qkTqTEnEn1413OX3.98.854103.45310Fcm第2章1、在N区耗尽区中,高斯定理为:DddAVsqEANv取一个圆柱形体积,底面在PN结的冶金结面(即原点)处,面积为一个单位面积,顶面位于x处。则由高斯定理可得:nDns0qExxxNxxmaxDsqEExNx当x=xn时,E(x)=0,因此,于是得:maxDnsqENx(2-5a)3、32ADbi220i510(1)ln0.026ln0.739V2.2510NNkTVqn5SpmaxA6SnmaxD125SbiSbidpnmax0max0(2)2.8310cm5.6710cm223.4010cmxEqNxEqNVVxxxEqNEqN124-10bimaxS2(3)4.3410VcmqNVE4、11112222SSbibidbibid000bibi22VVVxVVVVxqNqNVVbidd032VVxx当时,bidd083VVxx当时,D1D1D2D2nnnnnD1biD2203163D1D24bid0d1d1ddlnddddln|ln0.026V,110cm,110cm0.026ln(10)0.24VNNNNnJqDqnExDnkTnkTnEnxqnxqxNkTkTVExnqqNkTNNqV由平衡时多子电流为零得:将代入,得:6、ND2ND10120bimaxs153DADA0Dbi2DAi761d1d()d()d()exp()0.026V,0.4μm650Vcm2||10cm,ln0.757V,1.610kTnkTNxEqnxqNxxxkTNxNEqkTEqqNVENNNNkTNNVNNqnq、由第题:将代入,得:再将代入,得:突变结的最大电场强度表达式为:式中:1912S4maxmaxC,1.04510Fcm,||||1.5210VcmEE代入中,得:1D1D1i1n11Di1ns22max3A3A3ssi2p33Ai2psdN,d0()dI0,ddP,d0()ssEqqNENxCxqxxxEENxxxEEExEqqNENxCxqxxxEENxxx在型区,边界条件:在处,,由此得:在型区,常数在型区,边界条件:在处,,由此得:8、(1)0i1xi1nxxi2xi2pxxNIPsmaxi11maxDnnsDsmaxi23maxAppsA,,EqxxEENxxqNEqxxEENxxqN在处,由此得:在处,由此得:i2xi1x0E1E2maxEE3Ex0i1xi1nxxi2xi2pxxNIPi2pxxi1nxxi1i21Dn3ApsmaxDnApssIPN0,0,(),()0sqqxxENxxENxxqqxENxNx对于无型区的结:在处,电场达到最大,(2)maxbinpmaxEVxxE表面上,两种结构的的表达式相同,但由于两种结构的掺杂相同,因而相同(即电场曲线与横轴所围面积相同),所以两种结构的、与并不相同。0E1EmaxE3ExsmaxsmaxnpmaxDA120isbimax2s0i,211EExxEqNqNqNxVEqNx将代入,解出,得:120biimaxsimaximax2PN0,0qNVxExExE对于结,可令,得:当增大时,减小当时,DAbimaxnmaximaxp2ibimaxnipii1i2PIN11ln2222NNkTVExExExqnVExxxxxx对于结:式中,ppApAnnDnD2pidppD2nidnnAdpnpApAndnpnDpnD1exp1exp11qNNqNNqDnqVJLNkTqDnqVJLNkTJLDNNLJLDNLN已知:由于因此20、24、PN结的正向扩散电流为0expqVIIkT式中的I0因含ni2而与温度关系密切,因此正向扩散电流可表为2G1i2expexpEqVqVICnCkTkT于是PN结正向扩散电流的温度系数与相对温度系数分别为GGG222dexpdEqVEqVEqVICITkTkTkTG21ddEqVIITkT31、当N-区足够长时,开始发生雪崩击穿的耗尽区宽度为:BdBC221449μm32VxE当N-区缩短到W=3m时,雪崩击穿电压成为:22dBBBdB93'1144180V9xWVVx12s0T1bi2bibiTT2()0.6V,3V10pF,3.6103.6,0.2V103.610930(pF)0.4qNKCAVVVVKVVCKVC已知对于单边突变结,当时,由此可得因此当时,34、F0FFDFDDDDDDexpdd300K,0.026V,10mA0.01A1010.385s,2.626373100C0.0260.0323V,3001010.309s,3.2332.3qVIIkTIqIgVkTkTTIqgrgkTqgrg当时对于,在时,39、第3章1、NPN缓变基区晶体管在平衡时的能带图NPN缓变基区晶体管在放大区时的能带图2、NPN缓变基区晶体管在放大区时的少子分布图E0pC0pB0n3、C1B180IICCC2C10BBB2B1d100dIIIIIIIIBBnEBnEBBB241921nEBB123B2BEiBEBp0BBBBEBBi2i(0),(0),0.1cm,210cm,1.610C,15cms(0)8.3310cm(0)expexp(0)ln,(0)qDnJWJnWqDJAWqDnqVnqVnnkTNkTnNkTkTVnNnqnq由可得:将之值代入,得:又由,得:将、、及之值代BE226BBnBBBBn0.55V111,10s220.9987V入,得:已知:将及、之值代入,得:。6、7、211BbB2111.12510s2WD()8、以NPN管为例,当基区与发射区都是非均匀掺杂时,由式(3-33a)和式(3-33b),B222BiBEEBiBEnEBOB0exp1exp1dWqDnqVAqDnqVJkTQkTNxE222EiBEEEiBEpEEOE0exp1exp1dWqDnqVAqDnqVJkTQkTNx再根据注入效率的定义,可得:11pEBOEnEnEEnEpEnEBEB11JQDJJJJJJQD2BiBECEnCEnEEBB22BBBBB4219E211034BiB173BBEexp1110.99862210μm0.9986,1.610C,18cms,1.510cm,0.710cm10cm,0.7V,0.026VqDnqVIAJAJAWNkTWWLDAqDnWkTNVq式中,将,,之值代入,得:CCB4.55(mA)0.9936,155,0.029(mA)1III9、EEBOEEBBEBBBEOBBEBBE00119BOBBBEO2121EB111dd3.210C,1.2810C2cms,18cms,0.9972WWQDDWNDAqWNQDDNxDAqNxQAqWNQDD式中,,代入中,得:10、(1)(2)2BBB10.99992WD0.99713441,(3)(4)EOBBOEEOBBOE1'|'|'360,||4.7%QDQDQDeQD当由基区输运造成的亏损非常小时,可假设,这时可用来代替。误差为:14、BCbQI已知CBBb104II所以本题与第题的第()小题分别是两种极端情况。BBrB1QII若假设,则pBBEBBnBBnpnpnpBEEnEEpEEnpnpnpnpnp222**BBBnpnpnpBBnnpp*npnpnpnpnp11,1,,1,1,1222,,DWNDWNDWNDWNDWNDWNDkTDqDD,由可知,15、20、当忽略基区中的少子复合及ICEO时,B2BiBECnEEB0exp1dWqDnqVIIAkTNxBEBBBB2CCEBEEBi2oCEB0d()d1exp1dVWWNWIVqVAqDnrVkTNxBBBBCECB0d()ddWWNWVINxCAIVCBBABCEBdBCECBBEBBECECBAdBCB12sCbiCBdBBCB12dBsCCBBCBbiCB12BCBbiA0BsCdddd,dd,dd2()()dd2()()2()|VWVWVWxVVVWVVVVxVNVVxqNNNxNVqNNNVVqNNNVVWN对均匀基区,式中,因保持不变,所以于是:BBABBB0CEdd()dWWVNxNWV27、实质上是ICS。CB12BCBbiA0BsC2()|126VVqNNNVVWN22、33BCbi220i110ln0.026ln0.757V2.2510NNkTVqn使NBNC,这样集电结耗尽区主要向集电区延伸,可使基区不易穿通。39、为提高穿通电压Vpt,应当增大WB和NB,但这恰好与提高β相矛盾。解决方法:48、当IE很大时,这时α0α;当IE很小时,这时α0α;CBOECIII在IE很小或很大时,α都会有所下降。,0ddEI在正常的IE范围内,α几乎不随IE变化,这时,0ddEI,0ddEIβ0与β也有类似的关系。CE0EEEEdd()ddddIIIIII2EB02B1B21112RWRL口口TTC1T1C2T2TdcTTebbebeTETETEEC||1mA4100400MHz4mA4.5100450MHz500MHz,12()fffIfIffffkTkTrCCCqIqI