Device structures, fabrication methods, and design structures for a capacitor of a memory cell of ferroelectric random access memory device. The capacitor may include a first electrode comprised of a first conductor, a ferroelectric layer on the first electrode, a second electrode on the ferroelectric layer, and a cap layer on an upper surface of the second electrode. The second electrode may be comprised of a second conductor, and the cap layer may have a composition that is free of titanium. The second electrode may be formed by etching a layer of a material formed on a layer of the second conductor to define a hardmask and then modifying the remaining portion of that material in the hardmask to have a comparatively less etch rate, when exposed to a chlorine-based reactive ion etch chemistry, than when initially formed.