Relationship between process and materials variations and variations in S‐ and equivalent‐circuit parameters

Using a variety of DC and RF measurements of electrical parameters of GaAs MESFETs and the GATES process and device modeling program, we derive distributions of the root process variations. These distributions are then used in GATES Monte Carlo simulations to compute distributions of equivalent-circuit parameters and S-parameters at a fixed frequency (6 GHz). We find reasonable agreement between the simulated variations and the standard deviations in the measured S-parameters, enabling us to determine the most important process variations affecting S-parameter uniformity.