The following describes these two application tests:

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CV Curve Parameter Calculator: Calculates CMOS transistor parameters from capacitance versus voltage sweeps. (A.01.02)

[Description]
   Device parameters (Nsub, Cfb, Vfb, etc.) for an NMOS or PMOS transistor are calculated from the inputted CV curve using standard equations.

[Device Measured]
   No measurement performed; this application test does analysis only.  This application test is designed to be used inside of another application test.  Within the umbrella application test you can make the CV measurement using either a classic test C-V Sweep or another application test.  In fact, you do not need to use the B1500A MFCMU to make the CV measurement; you can also generate the CV curve with the SMUs using the QSCV function or with an external C-meter (such as a 4284A, E4980A or 4294A) that is being controlled by an application test.

[Device Parameters]
   Area: Area of the transistor gate (cm^2)
   TempC: Ambient temperature (degrees Celsius)
   Pm: Work function of the gate material (Volts)
   Device: Device type (NMOS=-1, PMOS=1)

[Test Parameters]
   Vsweep: Vector containing a minimum of 3 and a maximum of 1001 points representing the voltage applied to the transistor gate
   Cmeas: Vector containing a minimum of 3 and a maximum of 1001 points representing the measured gate-to-substrate capacitance

[Extended Test Parameters}:
   Autoscale: Variable to control auto scaling of the display (0=Off, 1=On)

[Measurement Parameters]
  None

[User Function]
  None

[X-Y Plot]
  X axis: Applied gate voltage (LINEAR)
  Y1 axis: Measured gate-to-substrate capacitance (LINEAR)

[List Display]
   Vsweep: Applied gate voltage (Volts)
   Cmeas: Measured gate-to-substrate capacitance (Farads)

[Parameter Display]
   Cox (Farads)
   Cmin (Farads)
   tox (Angstroms)
   ni (1/cm^3)
   Nsub (1/cm^3)
   Pfermi (Volts)
   Cfb (Farads)
   Vfb (Volts)
   Qsslq (1/cm^3)
   Qb (Coulomb/cm^2)
   Vth (Volts)

Note #1: Qsslq is "Qss over q".  This is the only compact way to represent this variable within EasyEXPERT.

Note #2: Sample QSCV and HFCV measurement data for a device is included with this application test.  Clicking on the input box for "Cmeas" will make softkey entries for these two data sets appear.  The other default parameters for this application test are correct for this data.

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Cgb with Parameters : Characterizes capacitance between gate and substrate versus gate voltage and uses this measurement data to compute device parameters.

This algorithm evaluates the capacitance between the gate and bulk (substrate) of a MOSFET. Fixed frequency and amplitude are applied to the gate, and the gate voltage is swept.

Using the gate area (in cm^2), temperature (in degrees Celsius) and work function of the gate material (in Volts), device parameters for the MOSFET (NMOS or PMOS) are caluculated using standard equations.

The outputs of this algorithm are in the following units:
Cox [Farads]
Cmin [Farads]
tox [Angstroms]
ni [1/cm^3]
Nsub [1/cm^3]
Pfermi [Volts]
Cfb [Farads]
Vfb [Volts]
QssOvrQ [1/cm^3]
Qb [Coulomb/cm^2]
Vth [Volts]