  The authors propose a new modeling approach based on the impedance field
method (IFM) to analyze the general geometric variations in device simulations.
Compared with the direct modeling of multiple variational devices, the proposed
geometric variation (GV) model shows a better efficiency thanks to its IFM
based nature. Compared with the existing random geometric fluctuation (RGF)
model where the noise sources are limited to the interfaces, the present GV
model provides better accuracy and wider application areas as it transforms the
geometric variation into global mesh deformation and computes the noise sources
induced by the geometric variation in the whole simulation domain. GV model
also provides great insights into the device by providing the effective noise
sources, equation-wise contributions, and sensitivity maps that are useful for
device characterization and optimization.
