A new self-align gated diamond field emitter array with sub-V turn-on voltage and high emission current

A new self-align gated diamond field emitter array with sub-V turn-on voltage and high emission current is reported for the first time. The new self-align gated diamond emitter array is fabricated by a new technique called "self-align-gate-molding". First, a silicon mold of inverted tips was fabricated on a p-type <100> silicon wafer via thermal oxidation, photolithographic patterning and anisotropic etching of silicon. A 0.7 μm high quality silicon dioxide layer gate dielectric was then grown on the Si inverted pyramidal mold using a dry thermal oxidation process, which at the same time produces a well-sharpened apex inverted pyramidal SiO/sub 2/ layer. Next, diamond was deposited by PECVD on the SiO/sub 2/ inverted sharpened pyramidal mold. A square window was then opened on the backside of the silicon mold and the silicon was then anisotropically etched until the SiO/sub 2/-covered diamond pyramidal apexes are exposed. Finally, the SiO/sub 2/ near the apex region was etched away to expose the sharpened diamond tips. The remaining SiO/sub 2/ and silicon form the gate dielectric and the gate (anode) respectively. The new self-align fabrication technique is simpler than the conventional self-align technique because fewer steps are used. Unnecessary deposition and etching steps of the conventional self-align process are removed. This results in a more uniform self-align gated structure with a sharper diamond tip apex and a more economical fabrication process.