A method that includes forming an opening between at least one first electrode and a second electrode by forming a recess in a first electrode layer, the recess having sidewalls that correspond to a surface of the at least one first electrode, forming a first sacrificial layer on the sidewalls of the recess, the first sacrificial layer having a first width that corresponds to a second width of the opening, forming a second electrode layer in the recess that corresponds to the second electrode, and removing the first sacrificial layer to form the opening between the second electrode and the at least one first electrode.