
Capacitance-Voltage
(C-V)
Measurements
3
GEORGE
N. MARACAS
The method of measuring free carrier (or doping) concentration profiles in semi-
conductors by capacitance-voltage (C-V)
relies
on modulating the depletion re-
gion in an MOS capacitor or field effect transistor (MOSFET), metal Schottky
barrier, electrolyte-semiconductor contact, or p-n junction by an applied voltage.
Superposition of a small ac voltage
onto
the dc bias allows the measurement of a
capacitance
of a thin region of doped material underneath a well-defined geometry
contact
(i.e.,
in which the area is precisely known). Scanning the reverse dc bias
from zero to the breakdow ...