A semiconductor device and a method for fabricating a semiconductor device are provided. The method for fabricating a semiconductor device includes forming an isolation layer over a semiconductor substrate defining first and second regions, etching the isolation layer at an edge of the first region to form a guard ring pattern, forming a buried guard ring filling the guard ring pattern, selectively etching the isolation layer of the first region to form a plurality of patterns, forming a plurality of conductive patterns in the respective patterns, and completely removing the isolation layer of the first region through a dip-out process.