Forming odd number of fins by sidewall imaging transfer

A method of forming a fin field-effect transistor (finFET) device, the method comprising the steps of:

• forming a pad layer on a substrate;
• patterning mandrels having a uniform width on the pad layer;
• forming a first pair of spacers on opposite sides of the mandrels;
• forming a second pair of spacers on a side of the first pair of spacers opposite the mandrels;
• removing the first pair of spacers selective to the mandrels and the second pair of spacers;
• patterning fin arrays in the substrate using a combination of the mandrels and the second pair of spacers as fin masks, wherein each of the fin arrays comprises the odd number of fins, wherein a spacing between the fin arrays is variable and independent of fin pitch within the fin arrays such that the spacing between the fin arrays is different from the fin pitch within the fin arrays, wherein the spacing between the fin arrays is based on a spacing between the mandrels as patterned, and wherein the step of patterning the mandrels comprises varying the spacing between the mandrels during the patterning of the mandrels to vary the spacing between the fin arrays;
• forming a gate over a portion of the fins that serve as a channel region of the finFET device;
• and
• forming doped source and drain regions on portions of the fins extending out from the gate.