Robust, scalable self-aligned platinum silicide process

A robust, scalable PtSix process is developed. The process consists of two consecutive annealing steps in a single run; the first is silicidation of Pt films on Si substrates carried out in N2, whereas the second is surface oxidation of the resultant PtSix in O2. By adequately adjusting the temperature during the oxidation step, a protective SiOx hard mask forms on PtSix of different thicknesses and compositions. Such a surface oxidation is absent for Pt on SiO2 isolation, which is crucial for the subsequent selective wet etch for a self-aligned process. Ultralong PtSix nanowires are fabricated using this robust self-aligned process.