A sub-0.1-micron PtSi Schottky source/drain MOSFET

Conventional MOSFETs are susceptible to short-channel effects such as punch-through and threshold voltage shift. Sub-0.1-{dollar}mu{dollar}m p-MOSFETs have been fabricated with PtSi sources and drains to avoid these effects. The interfaces of the PtSi sources/drains and the silicon channels form Schottky barriers that control the flow of holes. With an applied negative gate bias, field emission enables sufficient conductance of holes through the barrier. Without the applied bias, the barrier limits the hole current to thermionic emission and thus averts short-channel effects. Also, the Schottky devices are immune to bipolar effects such as latch-up and early source/drain breakdown, and have low contact resistances.; The devices are fabricated with lightly doped silicon substrates, 19-A to 34-A gate oxide, {dollar}sim{dollar}0.05-{dollar}mu{dollar}um gate lithography, 100-A sidewall oxides, self-aligned PtSi, and no intentional doping. The thin gate and sidewall oxides enable high field emission currents at low voltages. These devices exhibit on-state currents of 200-400 {dollar}mu{dollar}A/{dollar}mu{dollar}m and on-off ratios of 20 to 50. Cryogenic refrigeration of the devices reduce the off-state leakage current by several orders of magnitude.