The disclosed technology generally relates to semiconductor devices, and more particularly to FinFET transistors. In one aspect, at least three fins are arranged to extend in parallel in a first direction and are laterally separated from each other in a second direction by shallow trench isolation structures having a first fin spacing, where at least a portion of each fin protrudes out from a substrate. At least a portion of each of a first fin and a second fin of the at least three fins vertically protrude to a level higher than an upper surface of the shallow trench isolation structures. A third fin is formed laterally between the first fin and the second fin in the second direction, where the third fin has a non-protruding region which extends vertically to a level below or equal to the upper surface of the shallow trench isolation structures.