A method of making a semiconductor device includes forming at least one device layer over a substrate, forming at least two spaced apart features over the at least one device layer, forming sidewall spacers on the at least two features, filling a space between a first sidewall spacer on a first feature and a second sidewall spacer on a second feature with a filler feature, selectively removing the sidewall spacers to leave the first feature, the filler feature and the second feature spaced apart from each other, and etching the at least one device layer using the first feature, the filler feature and the second feature as a mask.