Keithley 4200A-SCS - Page 148

Model 4200A
-SCS Parameter Analyzer Reference Manual Section 4: Multi-frequency capacitance-vol
tage unit
4200A-901-01 Rev. C / February 2017 4-55
moscap-c-2vsv test
This test performs a C-V sweep and displays the inverse squared capacitance (1/C
2
) as a function of
the gate voltage (V
G
). This sweep can yield important information about doping profile because the
substrate doping concentration (N
SUB
) is inversely related to the reciprocal of the slope of the 1/C
2
versus V
G
curve. A positive slope indicates acceptors and a negative slope indicates donors. The
substrate doping concentration is extracted from the slope of the 1/C
2
curve and is displayed on the
graph. The doping concentration is the result of the NSUB Formulator calculation.
In the following equation, N (NDOPING) is related to the reciprocal of the slope of the 1/C
2
versus V
G
curve.
Where:
• N(W) = doping concentration (cm
-3
)
• A = gate area (cm
2
)
• C = measured capacitance (F)
• ε
s
= permittivity of the substrate material (F/cm)
• q = electron charge (1.60219 x 10
-19
C)
• V = gate voltage (V)
moscap-c-2vsv Analyze sheet
The test data is displayed in the Analyze sheet:
• Cp_GB: Measured parallel capacitance.
• Gp_GB: Measured conductance.
• DCV_GB: Forced DC bias voltage.
• F_GB: Forced test frequency.
• Formulas: Formulator calculation results.
GB = gate-to-bulk.