Abstract: A very high current ion implanted emitter is formed in a diffused base. Windows are made through the silicon nitride and silicon dioxide layes to both the base contact and the emitter regions using a resist mask. These regions are then protected by resist and the collector contact window is opened through the remainder of the silicon dioxide layer to the reach through region. A screen oxide is then grown in all the exposed areas after the removal of the resist mask. A resist mask is applied which covers only the base and Schottky anode regions. Arsenic is then implanted through the exposed screened areas followed by an etch back step to remove the top damaged layer. With some remaining screen oxide serving as a cap, the emitter drive-in is done.