Keithley 4200A-SCS Reference Manual page 1164

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