Size dependence of electrostatic lens effect in vertical MOSFETs

Abstract

The size dependence of the electrostatic lens effect in the channel of a nanoscale vertical pillar-type metal–oxide–semiconductor field-effect transistor (V-MOSFET) is studied by quantum dynamics simulation. Our findings indicate that the applicable diameter of the pillar for the efficient current-path control by the electrostatic lens effect on the V-MOSFET is in the range of about 10–30 nm. In the large-diameter pillar (30 nm diameter), the lens effect at the interfaces between the source and the body, and between the body and the source works well owing to the ballistic transport of electrons. On the other hand, in a slim pillar (10 nm diameter or less), the lens effect does not work well, because it is difficult to handle the electron dynamics by the analogy of classical geometrical optics, even though the electrons show ballistic transport. Our results indicate that the proposed technique is applicable for many nanoscale pillar-type devices.

Investigation of features for prediction modeling of nanoscale conduction with time-dependent calculation of electron wave packet

“…In our previous studies, the usefulness of electron time evolution calculation for design of nanoscale devices has been shown. [18][19][20][21] The advantages of the electron time evolution calculation are that the time evolution of the electron wavefunction can be visualized and that the time evolution of the wavefunction is treated as an initial value problem, so that the phenomena that occur with the time evolution can be naturally captured. For some of these advantages, device design using the time evolution calculation presents several challenges.…”

Improved drive-current into nanoscaled channels using electrostatic lenses

“…This has sparked new interest in applying electrostatic lenses in nanoelectronic devices, e.g. [6] suggests the use of lenses to focus electrons to the center of nanowires, thereby avoiding rough interfaces and increasing mobility.…”