[Audio] Physics of Nanoscale MOSFETs

While the previous lectures have been in the spirit of the bottom up approach, they did not follow the generic device model of Datta. In this lecture, the ballistic MOSFET theory will be formally derived from the generic model for a nano-device to show the connection explicitly.

The previous lessons developed an analytical (or almost analytical) theory of the nanoscale FET, but to properly treat all the details, rigorous computer simulations are necessary. This lecture presents quantum transport simulations that display the internal physics of nanoscale MOSFETs. We use these results to elucidate the physics discussed in previous lessons and to identify issues that still need to be clarified.

This lecture is a continuation of part 3A. After discussion some bandstructure considerations, it describes how 2D and subthreshold electrostatics are included in the ballistic model.

The IV characteristic of the ballistic MOSFET is formally derived. When Boltzmann statistics are assumed, the model developed here reduces to the one presented in Lecture 2. There is no new physics in this lecture - just a proper mathematical derivation of the approach that was developed intuitively in Lecture 2.

The previous lessons may seem a bit abstract and mathematical. To see how this all works, we examine measured data and show how the theory presented in the previous lessons help us understand the operation of modern FETs.

No MOSFET is ever fully ballistic - there is always some carrier scattering. Scattering makes the problem complicated and requires detailed numerical simulations to treat properly. My objective in this lecture is to present a simple, physical picture that describes the essence of the problem and that allows us to interpret the results of detailed simulations.

A very simple (actually overly simple) treatment of the nanoscale MOSFET. This lecture conveys the essence of the approach using only simple mathematics. It sets the stage for the subsequent lectures.

A quick review of the traditional theory of the MOSFET along with a review of key device performance metrics. A short discussion of the limits of the traditional (drift-diffusion) approach and the meaning of ballistic transport is also included.