Electrical transport in Schottky barrier MOSFETs

The motivation for this thesis originates in the semiconductor industry whose rapid economic growth in the past thirty years has been stimulated by scaling transistors to smaller dimensions. The current drive to design transistors beyond fundamental limitations is causing the industry to consider alternative structures. The Schottky Barrier (SB) MOSFET is one such device. It consists of metallic silicide source and drain contacts and a standard MOS gate. Previously, simulations have indicated that these transistors will have superior scaling properties and be more cost effective to fabricate than conventional transistors when channel lengths are scaled below 70 nm. This research experimentally investigates the current transport and scaling behavior of pSBMOSFETs fabricated on bulk silicon substrates.; We also explore the unique low temperature properties of Schottky Barrier (SB) MOSFETs. We find evidence that single charged impurities cause ‘hot spots’ that result in a reduced local potential at the abrupt metal/semiconductor interface. At relatively high temperatures (20–100 K) the impurities give rise to a non-uniform Schottky Barrier height. At lower temperatures electrons crossing the ∼8 nm barrier width are coherent, and a single impurity causes both enhanced direct tunneling and a resonant state due to the confined potential. As a result, we observe quantum interference between these two distinct paths of a single electron, known as a Fano resonance. Tuning of the interference is explored by varying temperature, bias direction and bias magnitude.