Ultrathin PtSi layers patterned by scanned probe lithography

Abstract

A process for patterning ultrathin layers of PtSi with high spatial resolution is presented. In this process, scanned probe anodic oxidation is used to pattern a surface oxide layer on a H-passivated Si surface. This oxide pattern prevents the reaction of a deposited Pt film with the underlying Si in the formation of PtSi. The unreacted Pt on the oxide is removed by a selective etch before any annealing. This process greatly reduces lateral diffusion and produces a 2-nm-thick PtSi layer with good electrical properties that maintains the fidelity of the patterned oxide mask. Such nanostructured PtSi films are a good candidate for use in constructing lateral Si-based quantum devices.