A method of making a semiconductor device includes forming at least one
device layer over a substrate, forming a plurality of spaced apart first
features over the device layer, where each three adjacent first features
form an equilateral triangle, forming sidewall spacers on the first
features, filling a space between the sidewall spacers with a plurality
of filler features, selectively removing the sidewall spacers, and
etching the at least one device layer using at least the plurality of
filler features as a mask. A device contains a plurality of bottom
electrodes located over a substrate, a plurality of spaced apart pillars
over the plurality of bottom electrodes, and a plurality of upper
electrodes contacting the plurality of pillars. Each three adjacent
pillars form an equilateral triangle, and each pillar comprises a
semiconductor device. The plurality of pillars include a plurality of
first pillars having a first shape and a plurality of second pillars
having a second shape different from the first shape.