Nanoelectronics Devices

  Scalability of MOSFETs

The Metal-oxide-semiconductor field-effect transistor (MOSFET) is by far the most successful and widespread electronic device. Scaling down the dimensions of MOSFETs has led to integration densities with billions of transistors fitting onto a few square centimeters of chip area. However, in order to avoid so-called short channel effects that lead to unacceptable leakage, the integration of novel materials and the implementation of new device architectures have been intensively studied recently. In addition, so-called steep slope transistors for the realization of highly integrated circuits with ultra low power consumption are currently investigated.

The present lecture deals with nanoelectronics devices, providing detailed insights into their device physics aspects, discussing the limitations as well as possible solution strategies.

  all-2D materials FET

Contents of the lecture:

The lecture starts with revisiting the classical MOSFET and its scaling towards the nanoscale. Before discussing nanoscale field-effect transistors and device concepts based on novel materials (such as graphene, transition metal dichalcogenides, carbon nanotubes etc.) the most important solid-state physics aspects are reviewed. This includes the band structure of solids in various dimensions (and tight binding calculations), density of states, computation of the carrier density, quantum transport etc. Next, a number of central ingredients of transistors such as the MOS capacitor and metal-semiconductor contacts are covered. Based on the described fundamentals, novel device concepts such as Schottky-barrier MOSFETs, reconfigurable FETs and steep slope transistors based on different materials and with various device architectures will be studied. Furthermore, the use of nanoelectronics devices in cryogenic electronics as required for the realization of e.g. cryogenic control electronics in quantum computation is elaborated on. In addition to simple models that allow predicting the device performance based on ballistic electronic transport, this lecture gives an introduction into device simulation techniques using the non-equilibrium Green’s function formalism.

Organization of the Lecture:

The course is not taught in the traditional way with two hours of lecture and one hour of exercise. Instead, the exercise is integrated into the lecture and students have to work with the lecture material in teams of 3-4 students during the lecture. The final examination is a written test.

The course will be offered regularly during winter terms and lays the foundation for the course Quantum Simulation of Carbon Nanotube and Graphene Nanoribbon Field-Effect Transistors.

Recommended literature includes: S. Datta: “Quantum Transport - Atom to Transistor”, S.M. Sze: “Physics of Semiconductor Devices”, and J. Knoch: “Nanoelectronics – Device Physics, Fabrication, Simulation”

Lecture dates and more information at RWTHOnline.