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- 81 -
q M -q ox = 3.15eVq ox -q Si = 3.1eVq s = q Si +E g/2+(E i -E Fs)
- 82 -
V G = V FB = M - S= MS =- 0.8V
- 83 -
(x)≡[E i (bulk)-E i(x)]/q
s≡[E i (bulk)-E i(0)]/q
F≡[Ei (bulk)-EF]/q = kTq ln (NA/n i) for p-type =- kTq ln (ND/n i) for n-type
s =2 F
≈-qNA ...0≤x≤W
W≈W max = 2 sqN A(2 F)
- 84 -
∙
∴
∴
s = 2 F
VT = VFB +2 F + |-Qd ( s = 2 F)|C oxQd=-qNAW=- 2 sqNA(2 F)
- 85 -
V QC = Q/ V
C(accu)≈C ox
C(depl) = C sC oxC s+C ox
QC( inv,LF)≈C ox
C( inv,HF) = C sC oxC s+C ox
- 86 -
μ
Δ
- 87 -
- 88 -
Q d( s = 2 F +V c)≈Q d( s = 2 F)V G≈V FB +2 F + - Q d ( s = 2 F)
C ox+V c+ - Q nC ox
= V TH+V c+ - Q nC ox
Q n =-C ox(V G -V T -V c)
V TH = V FB+2 F + - Q d ( s = 2 F)C oxQ d =-qN A W=- 2 sqN A(2 F)
- 89 -
J n≈J ny = q nnE y + qD ndn/dx≈q nnE y =- q nn dV cdyI D =- J nydxdz =-W x c(y)
0 J nydx
I D =-W nQ ndV cdy
Q d( s = 2 F +V c)≈Q d( s = 2 F) Q n≈- C ox (V G -V TH-V c)L
0 I Ddy≈ V D
0 W nC ox(V G -V TH-V c)dV c
I D = nC oxWL [ ( V G -V TH)V D -V 2D /2]
I Dsat = 12 nC oxWL ( V G -V TH) 2
- 90 -
i D = 12 nC oxWL [ (VG +v g)-VT] 2
= 12 nC oxWL (VG-VT) 2(1+ v gVG-VT
) 2
≈I D(1+2 v gVG-VT)
= I D +i d
∴i d = I D(V G-V T)/2 v g≡g mv g
Cgs≈23 C oxWL for saturation region
C gd≈CoxWL ov for saturation region
g d = IDVA
g m = I D(V G-V T)/2
i i = jW(Cgs +Cgd)vg i o(vd=0)≈gmvg
| i oi i(f=fT)|= gm2 fT(Cgs+Cgd) =1
f T = gm2 (C gs+C gd)
- 92 -
s = 2 F -VBS
V TH = V FB+2 F - Q IC ox- Q d( s = 2 F -VBS)
C oxQ d =-qNAW=- 2 sqNA(2 F -V BS)
V TH = V TH0+ ( 2 F -VBS- 2 F)V TH0 = V FB+2 F - Q IC ox
- Q d( s = 2 F)C oxand = 2 sqN A/C ox
- 93 -
I D = 12 nC oxWL (VG-VT) 2
ID=ID0eqVGnkT
(= 1n )≡ d sdVG= 11+d ox/d s
= 11+C d/C ox
n or ≡ ΔΔΔΔ
S≡ dVGd( log ID) = ln(10) dVGd( ln ID) = ln(10) kTq n = ln(10) kTq [1+Cd/Cox]
- 94 -
V DS≥V GS - V T
1 = 1lattice
+ 1impurity
+ 1surface
≈ 1surface
s = 01+U 0(V GS -V TH)
= s[1+[ E yE crit] 2]1/2
I D = 0[1+U 0 (V GS-V TH)] ×C 'oxW eff/L eff(1+ U 1L eff
V DS) × [ ( V GS -V T)V DS - a2 V2DS]
- 95 -
- 96 -
VT-VFB =2| B|+ |QD( eff)|Cox
Q'D = 1ZL [qx dmZ L+L'2 NA] = fQDwhere f=1- r jL {[1+ 2x dmr j
]1/2-1} < 1
VT =- qNAx dmr jC oxL ( 1+ 2x dmr j-1)
- 97 -
VT = 1+ x dmW
- 98 -
- 99 -
VT = V FB +2 F + -Q d ( s = 2 F)-Q IC ox
Q I =-qN I and Qd =-qNAW=- 2 sqNA(2 F)N I = 2.6×10 11boron ions/cm 2, x o=0.1 m
- Q I /C ox =+ 1.22V, V T= 1.0V