A method of forming a carbon nanotube fuse by depositing a carbon nanotube layer, then depositing a cap layer directly over the carbon nanotube layer. The cap layer is formed of a material that has an insufficient amount of oxygen to significantly oxidize the carbon nanotube layer under operating conditions, and is otherwise sufficiently robust to protect the carbon nanotube layer from oxygen and plasmas. A photoresist layer is formed over the cap layer, and the photoresist layer is patterned to define a desired size of fuse. Both the cap layer and the carbon nanotube layer are completely etched, without removing the photoresist layer, to define the fuse having two ends in the carbon nanotube layer. Just the cap layer is etched, without removing the photoresist layer, so as to reduce the cap layer by a desired amount at the edges of the cap layer under the photoresist layer, without damaging the carbon nanotube layer. The photoresist layer is removed, and electrically conductive contacts are formed on each of the two ends of the fuse.