50-NM LINEWIDTH PLATINUM SIDEWALL LITHOGRAPHY BY EFFUSIVE-SOURCE METAL PRECURSOR CHEMICAL-DEPOSITION AND ION-ASSISTED ETCHING

Vertical platinum sidewall structures 50 nm thick and 700 nm tall have been fabricated by Pt deposition from the thermal decomposition of tetrakis-(trifluorophosphine)-platinum using an effusive gas source followed by ion-assisted etching. Scanning electron microscope micrographs show that the sidewalls have high uniformity, very fine grains, and very sharp contours, demonstrating a high degree of conformal deposition. Scanning Auger microscopy confirms the presence of platinum only in the sidewalls. X-ray photoelectron spectroscopy analysis of the as-deposited platinum film reveals no detectable impurity and Scotch tape test shows good bonding of the film. The method is suitable to large-scale processing.