  The work estimates the minimum channel length of the MOSFET transistor, which
is the bacis device of modern electronics. Taking into account the real shape
of potential barrier in the channel shows that the electron tunnels through a
region significantly shorter than the physical length of the channel in the
presence of drain voltage, and so the available estimate of the minimum quantum
constraint channel length in silicon MOSFET, 1.2 nm, is significantly
underestimated. The fact makes it clear why after reaching 5 nm working lengths
of the channel it was impossible to reach the long-declared values of 3 nm
under maintaining the proper level of functionality of the transistor. The
estimates made in this work confirm that the fundamental scaling limits of
silicon MOSFETs have almost been reached.
