a non - volatile integrated device having first and second dimensionally different polysilicon gate layers separated by an oxide layer for hot - carrier reliability . more specifically , the oxide and second polysilicon gate layer are selectively etched to form a second gate region over the first polysilicon gate layer that electrically contacts the first polysilicon gate in one direction and is isolated by the oxide in the other direction . insulating sidewalls are formed over the first polysilicon gate layer regions that are not electrically contacted by the second gate layer to help isolate the second polysilicon gate and form an ldd structure within the substrate for the device .