Agilent Technologies EasyEXPERT, Manual, Page: 283 / 610

10 PwrDevice
10.8 Vth gmMax[3] PwrDevice: Linear region Vth (A.01.20)
[Supported Analyzer]
B1500A
[Description]
Extracts the threshold voltage (Vth) by using the extrapolation method for the linear region of the drain current
vs gate voltage characteristics.
[Device Under Test]
Power MOSFET, 3 terminals
[Device Parameters]
Polarity: Nch (SMUs force the specified value) or Pch (SMUs force the negative specified value).
Lg: Gate length
Wg: Gate width
Temp: Temperature
IdMax: Drain current compliance
[Test Parameters]
IntegTime: Integration time
Gate: SMU connected to Gate terminal, primary sweep voltage output
VgStart: Sweep start voltage for Gate terminal
VgStop: Sweep stop voltage for Gate terminal
VgStep: Sweep step voltage for Gate terminal
Drain: SMU connected to Drain terminal, constant voltage output
Vd: Drain voltage, ideally at around 100mV
Source: SMU connected to Source terminal, constant voltage output
BaseOffsetV: Base offset voltage
Base offset voltage is added to the specified voltage. For example, the gate start voltage will be
BaseOffsetV.
[Extended Test Parameters]
Vs: Source voltage
IgLimit: Gate current compliance
HoldTime: Hold time
DelayTime: Delay time
gm_Min: Minimum gm value for graph scale
gm_Max: Maximum gm value for graph scale
DrainMinRng: Minimum range for drain current measurement
[Measurement Parameters]
Drain current Idrain
[User Function]
gm=diff(Idrain,Vgate)
[Analysis Function]
gmMax=max(gm)
Von=@L1X (X intercept of Line1)
Vth=Von-Vd/2
Vth is given by the following formula.
Agilent EasyEXPERT Application Library Reference, Edition 8
10-15