Memory devices is provided, the memory devices include a tunneling insulating layer disposed on a substrate, a charge storage layer disposed on the tunneling insulating layer, a blocking insulating layer disposed on the charge storage layer and a control gate electrode disposed on the blocking insulating layer. The control gate electrode may have an edge portion spaced farther apart from the blocking insulating layer than a central portion of the control gate electrode to concentrate charge density distribution on a central portion of a memory cell.