Fundamental Limits for the MOSFET Conduction Channel Length Taking the Real Profile of the Barrier Potential into Account

The minimal length of the channel in the MOSFET, which is the principal device of modern electronics, has been estimated. The account of the real potential behavior in the channel demonstrates that, when some voltage is applied to the drain, electrons tunnel through a region that is essentially shorter than the physical channel length L. Therefore, the estimation of the minimal channel length in the Si-based MOSFET, which is available in the literature (L_min ≈ 1.2 nm), turns out substantially lowered. This discrepancy explains why, after having reached a working channel length of 5 nm, the value of 3 nm, which had been announced long ago, had not been achieved yet providing a proper level of the transistor functionality. The estimations made in this work confirm that the fundamental limits on the Si-based MOSFET scaling are currently almost reached. (author)