This paper presents robust algorithms to determine the parameters of the R3 nonlinear resistor model for both diffused and poly resistors. Extraction of many R3 parameters is simplified if it is based on the zero-bias conductance
, because
is not affected by velocity saturation or self-heating. We present techniques to reliably determine
, even when measured data are noisy or highly nonlinear, and show how to extract basic resistance parameters, temperature coefficients, and depletion pinching parameters using
. We describe how to determine thermal conductance parameters, and present a final parameter optimization strategy that prevents imprecision in modeling
from compromising the accuracy of fitting resistor nonlinearity.