A full complementary metal-oxide semiconductor (CMOS) static random access memory (SRAM) may have a reduced cell size by arranging a word line of a pair of transistors arranged on the uppermost layer of the SRAM. First and second transistors may be arranged on first and second active regions. Third and fourth transistors may be arranged on first and second semiconductor layers formed over the first and second active regions. Fifth and sixth transistors may be arranged on the third and fourth semiconductor layers over the first and second semiconductor layers. A word line may be arranged in a straight line between the first and second gates of the first and second transistors and between the third and fourth gates of the third and fourth transistors.