Keithley 4200A-SCS - Page 1164

Model 4200A
-SCS Parameter Analyzer Reference Manual Appendix D: Using a Model 82 C-V
System
4200A-901-01 Rev. C / February 2017 D-23
Formulas for ctsweep test (lifetime project)
Formula name Description and formula
NAVG
Average doping:
NAVG = 1E15
COX Oxide capacitance (in picofarads):
COX = 450
WF
Equilibrium inversion depth (in centimeters):
WF = ES*AREA*(1/MAX(CHF)-1E12/COX)
WWF
W - WF, where W is the depletion depth (in centimeters):
WWF = ES*AREA*(1/CHF-1E12/COX)-WF
GNI
Generation rate in S
-1
divided by intrinsic carrier concentration:
GNI = -(ES*AREA*NAVG*COX/1E12)*DIFF(1/CHF^2,TIME)/NI
Formulas for cvsweep test (stvs project)
Formula name Description and formula
VGS
Gate voltage:
VGS = -VSub
RS
Serial resistance calculated by high frequency CV:
RS = AT(MAVG(G_OR_R,5)/(WF*MAVG(CHF,5)),MAXPOS(MAVG(CHF,5))))^2/
((1+(AT(MAVG(G_OR_R,5)/(WF*MAVG(CHF,5)),MAXPOS(MAVG(CHF,5))))^2)
*(AT(MAVG(G_OR_R,5),MAXPOS(MAVG(CHF,5)))))
AR
Intermediate parameter for calculation of CC:
AR = G_OR_R-(G_OR_R^2+(WF*CHF)^2)*RS
CC
Corrected high frequency capacitance by compensating serial resistance:
CC = ((G_OR_R^2+(WF*CHF)^2))*CHF/(AR^2+(WF*CHF)^2)
HOFFSET
Offset for high frequency capacitance (entered by user):
HOFFSET = 0
DELAY
595 delay time:
DELAY = 0.15
HGAIN
Gain for calculated high frequency capacitance that is calculated:
HGAIN = AT(MAVG(CQS,5)/MAVG(CC,5),MAXPOS(MAVG(CC,5)))
CHADJ
Adjusted high frequency capacitance by using HGAIN and HOFFSET:
CHADJ = HGAIN*CC+ HOFFSET
VSTEP
595 step voltage:
VSTEP = 0.02
LEAKSLP
Average slop of leakage current neglecting the contribution of mobile ion:
LEAKSLP = LINEFITSLP(VGS, QT, 49, 200)
49 and 200 are indexes on QT array to fit the slope.
QGAIN
Gain for quasistatic capacitance (entered by user):
QGAIN = 1
CQADJ
Adjusted quasistatic capacitance by using QGAIN and QOFFSET:
CQADJ = QGAIN*CQS+QOFFSET
NM
Mobile ion density:
NM = AVG((CQADJ- CHADJ)*ABS(DELTA(VGS))*(LASTPOS(DELTA(VGS))-
FIRSTPOS(DELTA(VGS)))/Q/AREA