A physical-based analytical model to predict the fluctuations in threshold voltage induced by a single interface trap at a random location along the channel in a typical sub-50-nm MOSFET is of utmost significance. In this letter, simulation results from two different analytical models and particle-based device ensemble Monte Carlo schemes are used to compute threshold voltage variation in the presence of interface traps at a certain location in the channel. These results provide clear evidence that, without the accurate short-range Coulomb force correction, the analytical models will provide inconsistent V T for traps located near the source of the MOSFET device with 32-nm effective channel length.Index Terms-Random dopant fluctuations (RDFs), random interface trap, short-range Coulomb interaction, threshold voltage variation.