As all time ramps are linear, a boost step of 1 to 3 s on an etch step of 2 to 4 s effectively means that the etch time remains constant at 1 s. Lengthening the boost step ensures full fluorocarbon removal for the whole depth of the nanopore and the etch step proceeds for 1 s at all cycles in the etch. As these conditions give a very straight pore profile, it seems that enough reactive species reach the bottom of the pore even at full depth, hence 1 s is sufficient for etching after the removal of fluorocarbon.