semiconductor 66

undoped

NiggersF

qeptor1 I IN P Ne n Np f NAForse ne 1.5 10 an p n n n n

z PNxp NE MassAction ND

Drift currentlaw

J gE CnqUntP8µp ETmobility

f Yz i R f i fDiffusionCurrent

Jp GDpl ddIxi Ctf J

xJn C 8 Dnf done 8DnddIx

At equilibrium

Jp O PfUpE GDpddIx

Jn o nqUnE qDndn_DXExample Non uniform doping profile

Jp o PCx pE ftp.dpdxNA10Dqn kTq V EinsteinRelation

ecxj Vi.pt dPhole tf DXJpdiff lo's 10 1Eth 1µm an

N ion te21 0 P 1018 E 0.9 1044

EF drift

Klum F 10 C 9 1044

P n Junction IForwardBeas1

FIFTH TDDonorcharge

qq.li ifilk v

Epmdelectron

Depletion widthNoentarge narrows

c dxX Emax reduces

Er Traits Nee current Jp o

p c e Jp drift Jn D

Boltzmann Jndiff GE L Jnidirite fEh i Eaa V applied voltage

igniting eEYfiFNa XP 0 Xn minority carrier at X Xp

underforwardinnit i oh P Ee IY oo

pIpn opncxy oPncxxn EExponentially decrease

1 with Lp diffusionlength

Pp Na pno.E pp e FT.IN NnpNay

niVo Vt.lnNAf No

In depletion regionboth F diff Jp drift

Indeff Ju driftInstead we estimate currentat X Xn charge neutral region

C 0

Only diffusion current

Fdiff f Dp.dkdXfppd.oPnCX

dX

fDpffpoPnCx Xn7

ftp.pnoce t

similarly9 n ce D

Tn.ae KDnnnfzcEt

DJtotalJp.deatJn.dea ffIfnNEp EDITna

e D

I Jtotal Area Is e D XIn

SpnCX 0PntxXn e

a eat d.dk fzgnPnaxnItEpIE FfoPntxfnLp