Agilent Technologies EasyEXPERT, Manual, Page: 106 / 610

2 CMOS
2.28 Vth Const Id: Constant current Vth (A.01.20)
[Supported Analyzer]
B1500A, 4155B, 4155C, 4156B, 4156C
[Description]
Measures the drain current vs gate voltage characteristics, and extracts the threshold voltage (Vth) by using
the constant current method.
[Device Under Test]
MOSFET, 4 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
Id@Vth: Drain current to decide the Vth
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
Subs: SMU connected to Substrate, constant voltage output
Vsubs: Substrate voltage
Source: SMU connected to Source terminal, constant voltage output
[Extended Test Parameters]
Vs: Source voltage
IgLimit: Gate current compliance
IsubsLimit: Substrate current compliance
HoldTime: Hold time
DelayTime: Delay time
DrainMinRng: Minimum range for the drain current measurement
[Measurement Parameters]
Drain current Idrain
[User Function]
gm=diff(Idrain,Vgate)
[Analysis Function]
Vth=@L1X (X intercept of Line1)
[X-Y Plot]
X axis: Gate voltage Vgate (LINEAR)
Y1 axis: Drain current Idrain (LINEAR)
Y2 axis: Drain current Idrain (LOG)
[List Display]
Transconductance gm
[Parameters Display Area]
Threshold voltage Vth
[Auto Analysis]
Line1: Vertical line for Y1 at Idrain=Id@Vth
Agilent EasyEXPERT Application Library Reference, Edition 8
2-44