A method for forming a semiconductor structure for a memory device, including providing a substrate comprising a memory cell region and a peripheral circuit region defined thereon, and the peripheral circuit region comprising at least an active region formed therein, forming at least a buried gate structure in the active region, and an insulating layer being formed on a top of the buried gate structure, and forming a conductive line structure on the buried gate structure, and the conductive line structure and the buried gate structure being physically spaced apart and electrically isolated from each other by the insulating layer.