Section 4: Multi-frequency capacitance-voltage unit
Model 4200A-SCS Parameter Analyzer Reference Manual
4-88
4200A-901-01 Rev. C / February 2017
Diode Project (diode-project)
This project contains DC I-V, C-V, and pulse I-V tests for a PN junction.
The
diode
project measures the capacitance of a pn junction or Schottky diode as a function of the
DC bias voltage across the device. The PN junctions must be highly asymmetrical p+n or n+p
junctions, which means that one side of the junction is much more highly doped than the other side. If
this is the case, the effects of the space charge region spreading into the more highly doped area can
be ignored.
C-V measurements on semiconductor junctions are based on the fact that the width (
W
) of the
depletion region of the junction is not constant, but varies with the DC voltage across the junction.
This capacitance, related to the space charge region of the semiconductor junction, is known as the
junction capacitance. This concept is illustrated in the next figures, showing a reverse-biased
Schottky diode and a reverse-biased p+n junction.
Figure 137: Reverse-biased Schottky diode
Figure 138: Reverse-biased p+n junction
