Optically transparent PtSi Schottky contacts on silicon—structure and electrical properties

Abstract

Very thin (60–160 Å) PtSi films, meant for optically transparent Schottky contact application in silicon photodetectors have been prepared by magnetron sputtering of platinum onto heated silicon substrates, followed by in situ annealing in vacuum. Auger electron spectroscopy (AES), X-ray diffraction and optical reflectivity measurements, and high resolution transmission electron microscopy (TEM) were used to study composition and microstructure of the films. The results show complete formation of PtSi, with grains of average size of 300 Å, growing epitaxially to the silicon substrate even at film thickness of 160 Å. Further, we found that even our thinnest PtSi films (with R s ∼ 900 ω □ −1) yield perfect diodes on n-type silicon with leakage current of 1.2–1.5 nA cm −2.