The semiconductor device including a substrate comprising a chip region and a guard-ring region which surrounds a side surface of the chip region, an isolation layer configured to define an active region within the guard-ring region, a first doping layer in the active region and doped with first impurities having a first doping concentration, a second doping layer on the first doping layer and in the active region, the second doping layer doped with second impurities having a same conductivity type as the first impurities of the first doping layer, the second impurities having a second doping concentration, the second doping concentration being greater than the first doping concentration, a first gate electrode on the second doping layer, and a first wire layer on the first gate electrode may be provided.