A self‐aligned process that generates 18 μΩ‐cm contacts and interconnects with no bridging above or encroachment under oxide sidewall spacers is demonstrated using a 700°C rapid thermal anneal of sputter‐deposited cobalt followed by a selective etch. Auger electron spectroscopy, transmission electron microscopy, electron diffraction, spreading resistance, secondary ion mass spectrometry, current‐voltage, and surface photovoltaic measurements are employed for material and electrical characterization. With increasing temperature, cobalt films on Si(100) are transformed into , , and, finally, , the maximum in sheet resistance coinciding with the completion of monosilicide formation. Although oxygen is initially snowplowed out of the growing silicide layer towards the surface, voids containing oxygen remain in the uppermost portion of the eventual silicide film. At high temperatures, films on break up into globules that cause pitting of the thermal oxide surface. Shallow p+/n junction diodes, formed by boron implantation either before or after cobalt deposition and activated using the silicidation anneal, display excellent electrical characteristics. The electrical properties are improved by a 900°C, 30 min furnace postanneal, while the boron concentration at the interface is reduced by outdiffusion.