In this work, we study the effect of interface traps (ITs) and random dopants (RDs) on characteristics of 16-nm MOSFETs. Totally random generated devices with 2D ITs between the interface of silicon and HfO2 film as well as 3D RDs inside the silicon channel are simulated. Fluctuations of threshold voltage and on/off state current for devices with different EOT of insulator film are analyzed and discussed. The results of this study indicate ITs and RDs statistically correlate to each other and RDs govern device variability, compared with the influence of ITs. Notably, the position of ITs and RDs induces rather different fluctuation in spite of the same number of ITs and RDs are investigated.