A MOS transistor is described, including: a source region and a drain region in a semiconductor substrate, an isolation between the source region and the drain region, a first gate conductor between the source region and the isolation, at least one conductive plug electrically connected to the first gate conductor and penetrating into the isolation, and at least one second gate conductor on the isolation, which is electrically connected to the first gate conductor and the at least one conductive plug. One of the at least one conductive plug is between the first gate conductor and the at least one second gate conductor.