An electrode structure for a display device comprising a gate electrode proximate to an emitter and a focusing electrode separated from the gate electrode by an insulating layer containing a ridge. When the focusing electrode is an aperture-type electrode, the upper surface of the ridge protrudes closer to the emitter than the sidewall of the gate electrode or the sidewall of the focusing electrode. When the focusing electrode is a concentric-type electrode, the ridge protrudes above the upper surface of the gate electrode or the upper surface of the focusing electrode. A method for making the aperture-type and concentric-type electrode structures is described. A display device containing such electrode structures is also described. By forming an insulating ridge between the gate and focusing electrodes, shorting between the two electrodes is reduced and yield enhancement increased.