A memory array comprises a plurality of memory cells arranged in columns and rows. The memory array also comprises a plurality of first-type strap cells arranged in a row, wherein each first-type strap cell comprises a first-type well strap structure. The memory array further comprises a plurality of second-type strap cells arranged in a row. Each second-type strap cell comprises a second-type well strap structure. Each column of memory cells is bracketed by at least one first-type strap cell of the plurality of first-type strap cells or at least one second-type strap cell of the plurality of second-type strap cells.