Accurate Statistical Description of Random Dopant-Induced Threshold Voltage Variability

We have studied the detailed threshold voltage distribution in a state-of-the-art n-channel MOSFET in the presence of random discrete dopants. A ground-breaking sample of 100 000 transistors with statistically unique random dopant distributions were simulated using the Glasgow 3-D device simulator and advanced grid computing technologies. The results indicate that the threshold voltage distribution deviates substantially from a Gaussian distribution, which may have significant implications for the margins used in circuit design, particularly in SRAM cells.