Analysis of extra VT variability sources in NMOS using Takeuchi plot

Extra V
T
variability sources in NMOS are investigated using Takeuchi plot. It is clearly shown that V
T
variation of boron channel NMOS cannot be explained solely by the channel depth profiles. Moreover it is clarified that boron TED is the dominant source of the extra NMOS V
T
variability. By suppressing the effect of boron TED with backward substrate bias, V
T
variation of boron channel NMOS comes close to that of phosphorus channel PMOS.