| The goal of this work is theoretical analyses of two prospective nanoelectronic devices. The first of them, the metal-oxide-semiconductor field-effect transistor (MOSFET) is the cornerstone of present day integrated circuit technology. We explore the ultimate size scaling limits of MOSFETs as their critical feature dimensions are scaled down below 10 nm. At that size, the physics of electron transport in these devices radically changes from quasi-equilibrium drift-diffusion to ballistic propagation. A proper description of such a regime requires a quantitative account of two-dimensional electrostatics and quantum mechanical effects such as direct source-to-drain tunneling. We have carried out extensive numerical simulations of nanoscale transistors, including these effects, using a self-consistent solution of the Poisson and Schrodinger equations. The results show that advanced silicon transistors can provide voltage gain at gate lengths as small as 4 nm. However, the device sensitivity to unavoidable variations of the dimensions during fabrication, and power consumption grow exponentially in this regime.;The second device under study, the superconductor balanced comparator, is based on the quantum mechanical quantization of flux through superconducting loops. This device is a key component of Rapid Single-Flux-Quantum (RSFQ) circuits which can be used for digital signal processing at sub-THz frequencies, with extremely small power consumption, albeit at deep refrigeration. Alternatively, the comparator may be used for measurement of current (or magnetic flux) with sub-picosecond time resolution. We show that the signal detection sensitivity of the balanced comparator, with realistic parameters, may be limited only by the fundamental quantum fluctuations. |
