L02-双极型晶体管

1/149半导体器件原理主讲人：蒋玉龙本部微电子学楼312室，65643768Email:[e-mail]第二章双极型晶体管2.1基本结构、制造工艺和杂质分布2.2电流放大原理2.3直流特性2.4反向特性2.5晶体管的模型2.6频率特性2.7开关特性3/1492.1基本结构、制造工艺和杂质分布12.1.1晶体管的基本结构n+pnEBC发射区基区集电区p+npEBC发射区基区集电区ECBnpnECBpnp4/1492.1基本结构、制造工艺和杂质分布22.1.2制造工艺合金管平面管5/1492.1基本结构、制造工艺和杂质分布32.1.3杂质分布均匀基区缓变基区基区内载流子传输方式自建电场扩散扩散漂移+扩散型晶体管漂移型晶体管6/149第二章双极型晶体管2.1基本结构、制造工艺和杂质分布2.2电流放大原理2.3直流特性2.4反向特性2.5晶体管的模型2.6频率特性2.7开关特性7/1492.2电流放大原理12.2.1放大条件放大条件：1、WbLnb2、发射结正偏3、集电结反偏n+pnEBCIeIcIbRERLVbeVcb8/1492.2.2电流传输2.2电流放大原理2peneeIIIcbonccIIIcbovbpebIIIIIneInccbeIII9/1492.2.3共基极电流放大系数2.2电流放大原理30cbVecII11nccnenceneecIIIIIIII**集电区倍增因子基区传输系数发射效率（注入比）nepepeneneeneIIIIIII111（当Ne/Nb1时）nevbnevbnenencIIIIIII1*1（当WbLnb时）IeIbIcVbeVcbcbeIII10/1492.2.4共射极电流放大系数2.2电流放大原理41cecVbcIIIIIce1IbIeIcVbeVce11/149第二章双极型晶体管2.1基本结构、制造工艺和杂质分布2.2电流放大原理2.3直流特性2.4反向特性2.5晶体管的模型2.6频率特性2.7开关特性12/1492.3.1晶体管中的少子分布2.3直流特性1kTqVnnbepbpbexp)0(0kTqVnWnbcpbbpbexp)(00kTqVpxpbeneneexp)(01kTqVpxpbcncncexp)(020x2N+PNWb0x-x1x2EcpEcnEvpEvnEfpEfnqVq(VD–V)pxnxEcpEcnEvpEvnEfpEfnqVq(VD-V)13/1492.3.2理想晶体管的电流-电压方程2.3直流特性2假设：突变结一维（Aje=Ajc=A）外加偏压全加在结上忽略势垒区的产生-复合电流小注入1.少子分布(1)基区0)()(2022nbpbpbpbLnxndxxndkTqVnnbepbpbexp)0(0kTqVnWnbcpbbpbexp)(000Wb基区均匀掺杂nnbnbDL2nbbnbbpbnbbpbpbpbLWLxWnLxWnnxnsinhsinh)(sinh)0()(0WbLnbbbepbWxkTqVn1exp014/1492.3.2理想晶体管的电流-电压方程2.3直流特性31.少子分布(2)发射区0)()(2022peneneneLpxpdxxpdkTqVpxpbeneneexp)(010)(neneppWeLpepeneneneLxxxppxp110exp)()(WeLpe且0)(1eneWxpebeneneWxxkTqVpxp101exp)(0Wb-x1x20WbWe-x1x215/1492.3.2理想晶体管的电流-电压方程2.3直流特性41.少子分布(3)集电区0)()(2022pcncncncLpxpdxxpdkTqVpxpbcnencexp)(020)(ncncpp(WcLpc)0exp1)(20pcncncLxxpxp0Wb-x1x216/1492.3.2理想晶体管的电流-电压方程2.3直流特性52.电流密度(只计算扩散电流)(1)基区中电子电流dxxdnqDJpbnbnb)(nbbnbbpbnbbpbnbnbLWLxWnLxWnLqDsinhcosh)(cosh)0(0Wb-x1x2nbbnbbpbnbbpbpbpbLWLxWnLxWnnxnsinhsinh)(sinh)0()(017/1492.3.2理想晶体管的电流-电压方程2.3直流特性62.电流密度(只计算扩散电流)(1)基区中电子电流0WbJnb(0)Jnb(Wb)nbbbpbnbbpbnbnbnbLWWnLWnLqDJsinh)(cosh)0()0(nbbnbbbpbpbnbnbbnbLWLWWnnLqDWJsinhcosh)()0()(nbbnbbbpbpbnbnbbnbnbLWLWWnnLqDWJJsinh1cosh)()0()()0(JvbWbLnbkTqVWnqDxJbebpbnbnbexp)(0=常数=Jnb(0)=Jnb(Wb)0问题：上述结论也可从载流子线性分布直接推出.问题：考虑复合时，少子如何分布？a还是b?kTqVnbepbexp00Wbab18/1492x2.3.2理想晶体管的电流-电压方程2.3直流特性72.电流密度(只计算扩散电流)(2)发射区中空穴电流1exp)(01kTqVLpqDxJbepenepepe(3)集电区中空穴电流1exp)(02kTqVLpqDxJbcpcncpcpcWeLpepeneneneLxxxppxp110exp)()(WcLpcexp1)(20pcncncLxxpxp19/1492.3.2理想晶体管的电流-电压方程2.3直流特性83.Ie、Ib、Ic表达式(1)Ie表达式)()0()()(111xJJxJxJJpenbpenee1expcoth00kTqVLpDLWLnDqbepenepenbbnbpbnb1exphcsc0kTqVLWLnqDbcnbbnbpbnb1exp1exp1211kTqVakTqVaAJIbcbeeepenepenbbnbpbnbLpDLWLnDqAa0011cothnbbnbpbnbLWLnqADahcsc012EBCIeIbIcxJe,Jc2x20/1492.3.2理想晶体管的电流-电压方程2.3直流特性93.Ie、Ib、Ic表达式WbLnb时，且放大偏置bpbnbbepenepebpbnbeWnqDkTqVLpDWnDqJ0001exppenepebpbnbLpDWnDqAa0011bpbnbWnqADa0121exp1exp1211kTqVakTqVaIbcbee1expexp00kTqVLpqDkTqVWnqDbepenepebebpbnb(1)Ie表达式21/1492.3.2理想晶体管的电流-电压方程2.3直流特性103.Ie、Ib、Ic表达式(2)Ic表达式)()()()(222xJWJxJxJJpcbnbpcncc1expcoth00kTqVLpDLWLnDqbcpcncpcnbbnbpbnb1exphcsc0kTqVLWLnqDbenbbnbpbnb1exp1exp2221kTqVakTqVaAJIbcbecc12021hcscaLWLnqADanbbnbpbnbpcncpcnbbnbpbnbLpDLWLnDqAa0022cothEBCIeIbIcxJe,Jc2x22/1492.3.2理想晶体管的电流-电压方程2.3直流特性113.Ie、Ib、Ic表达式(2)Ic表达式WbLnb时，且放大偏置1exp1exp2221kTqVakTqVaIbcbecpcncpcbpbnbbebpbnbcLpDWnDqkTqVWnqDJ0001exp12021aWnqADabpbnbpcncpcbpbnbLpDWnDqAa002223/1492.3.3、表达式2.3直流特性121.表达式=**)0()(11111nbpenepeeneJxJJJJJ(1)1111pebbepebebnepbLWLWNNWeLpe11ebbeWW2x1001001tanh1pebpbnenbpenbbpenbpbnenbpeLWnpDDLWLLnpDD24/1492.3.3、表达式2.3直流特性131.表达式=**(1)11pebbeLW定义方块电阻eeeshWR,bbbshWR,1,,1bsheshRR要则要Rsh,e/Rsh,bNe/NbsRntnWtWnSLRWt电流IWL薄层电阻推导示意图25/1492.3.3、表达式2.3直流特性141.表达式=**(2)*)0()(*nbbnbnencJWJJJ放大偏置时)exp(coth)0(0kTqVLWLnqDJbenbbnbpbnbnb)exp(hcsc)(0kTqVLWLnqDWJbenbbnbpbnbbnb22*21hsec)0()(nbbnbbnbbnbLWLWJWJ要*则要WbLnbnb2x26/1492.3.3、表达式2.3直流特性141.表达式=**(3)*=11211212222**nbbpebbepebbenbbLWLWLWLW11pebbeLW22*21hsec)0()(nbbnbbnbbnbLWLWJWJ2.表达式1222111nbbpebbeLWLW127/1492.3.4理想晶体管的输入、输出特性2.3直流特性151.共基极IE/mAVBE/VVCB输入特性输出特性IeIbIcVbeVcb28/1492.3.4理想晶体管的输入、输出特性2.3直流特性162.共射极VCE输入特性输出特性IbIeIcVbeVce29/1492.3.5晶体管的非理想现象2.3直流特性171.发射结结面积对的影响n+pnAje*AjeoIne’Ine本征基区：WbLnb非本征基区：WbLnb**jenejeojepenepeAJAAJII1***'1