Modifications of fillet structures to form tip emitters

In order to reduce the turn-on voltage of vacuum microelectronic devices, it is desirable that the field enhancement of the emitter be maximized. We have previously developed a gated manufacturable emitter process which uses fillets as emitters. Since tips have higher field enhancement then fillets we have tried to adapt our process to incorporate tip emitters. Two different approaches have been developed to try to achieve this goal. The first approach employs a sputter etch to form a tip on the end of a spike. Unfortunately, the tip formed is not sufficiently sharp enough to reduce the turn on voltage. In the second approach, the corners of a mold are sharpened during the deposition of the spacer material. The emitter material is then deposited and following the removal of the spacer, a very sharp tip remains