Forming narrow fins for finFET devices using asymmetrically spaced mandrels

A method of forming fin-shaped field effect transistor (finFET) devices, the method comprising:

• forming a plurality of sacrificial mandrels over a semiconductor substrate, the plurality of sacrificial mandrels being spaced apart from one another by a first distance along a first direction, and by a second distance along a second direction;
• forming spacer layers on sidewalls of the sacrificial mandrels such that portions of the spacer layers between sacrificial mandrels along the first direction are merged together and portions of the spacer layers between sacrificial mandrels along the second direction remain spaced apart;
• removing the sacrificial mandrels;
• transferring a pattern corresponding to the spacer layers into the semiconductor layers to form a plurality of semiconductor fins, wherein adjacent pairs of fins are merged with one another at locations corresponding to the merged spacer layers;
• forming one or more gate conductors over the plurality of semiconductor fins;
• and
• forming contact regions on merged portions of the semiconductor fins.