Abstract: A method for producing an NPN semiconductor device which has a titanium-tungsten barrier metal only in the N type contact windows is disclosed. A semiconductor wafer first undergoes the washed emitter process with the result that the N type collector and emitter contact windows are exposed to bare silicon and the P type contact windows are covered by a layer of silicon dioxide. A layer of titanium-tungsten alloy is deposited on the surface of the wafer. The titanium-tungsten layer is etched out of the P type contact regions using standard photolithographic techniques. The underlying layer of silicon dioxide in the P type contact regions is then also etched away. A layer of aluminum is then deposited across the surface of the wafer. The conductor interconnect photolithography is used to etch away all undesired aluminum. The remaining portions of the titanium-tungsten layer, not covered by aluminum signal lines, are then also etched away.