A method includes forming a patterned gate stack for a memory device, the patterned gate stack including a gate insulation layer, a charge storage layer, a blocking insulation layer and a gate electrode, the gate insulation layer and the blocking insulation layer having an initial width. An etching process is performed on the patterned gate stack to selectively remove at least a portion of each of the gate insulation layer and the blocking insulation layer, the etching process reducing a width of each of the gate insulation layer and the blocking insulation layer from the initial width to a final width. After performing the etching process, at least one material layer is formed proximate sidewalls of the patterned gate stack, the at least one material layer laterally confining each of the gate insulation layer, the charge storage layer, the blocking insulation layer, and the gate electrode.