| CPC H01J 37/073 (2013.01) [H01J 37/28 (2013.01); H01J 2237/2812 (2013.01)] | 18 Claims |

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1. An electron gun including a field emitter configured to generate a primary electron beam, wherein the field emitter comprises:
a monocrystalline silicon substrate having opposing first and second surfaces and including at least one integral field emitter protrusion, the field emitter protrusion having a fixed portion integrally connected to the silicon substrate and extending from the second surface to a tip portion; and
a titanium nitride (TiN) layer hermetically disposed at least on the tip portion of the field emitter protrusion such that, during operation, electrons leaving the monocrystalline silicon substrate through the tip portion to form the primary electron beam only pass through the TiN layer, wherein the TiN layer comprises at least 75 atomic percent TiN, and wherein a portion of the TiN layer located within a radius of 100 nm from the tip portion comprises less than 10 atomic percent carbon.
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