A method of forming a memory device on a substrate having memory, core and HV device areas. The method includes forming a pair of conductive layers in all three areas, forming an insulation layer over the conductive layers in all three areas (to protect the core and HV device areas), and then etching through the insulation layer and the pair of conductive layers in the memory area to form memory stacks. The method further includes forming an insulation layer over the memory stacks (to protect the memory area), removing the pair of conductive layers in the core and HV device areas, and forming conductive gates disposed over and insulated from the substrate in the core and HV device areas.