A memory cell array includes a first memory cell arranged in a first row in a first direction and a second memory cell arranged in a second row in the first direction. The first memory cell or the second memory cell includes a set of active regions, a set of gates and a first set of conductive structures. Each of the active regions of the set of active regions is separated from an adjacent active region in the first direction by a first pitch. The set of active regions extends in a second direction. The set of active regions includes a first active region adjacent to a first side of the first memory cell, and a second active region adjacent to a second side of the first memory cell. A length of the first active region is different from a length of the second active region.