Modeling Statistical Dopant Fluctuations Effect on Threshold Voltage of Scaled JFET Devices

This paper presents a simple mathematical expression to model the effect of statistical dopant fluctuations on threshold voltage (V
_th
) of junction field-effect transistors (JFETs). The random discrete doping (RDD) in the active device area is used to derive an analytical model to compute the standard deviation, σV
_th
,RDD of the V
_th
-distribution for any arbitrary channel doping profiles. The model shows that the Vth-variability in JFETs depends on the active device area, channel doping concentration, and the depth of the channel depletion region of the gate/channel pn-junction. The model is applied to compute σV
_th
,RDD for symmetric and asymmetric source/drain double-gate n-channel JFETs. The simulation results show that the model can be used for predicting V
_th
-variability in JFETs.