A semiconductor device is disclosed. The semiconductor device including writing and reading gate electrodes respectively on first and second active regions on a substrate, a first gate insulation pattern between the first active region and the writing gate electrode, a second gate insulation pattern between the second active region and the reading gate electrode, first and second source/drain junction regions in the first and second active regions at sides of the writing and reading gate electrodes, and a connection structure that connects the first and second source/drain junction regions. The first active region has the same conductivity type as the source/drain junction regions. The second active region has a different conductivity type from the source/drain junction regions.