Method for forming electron emitters

A method for manufacturing emitters, said method comprising the following steps of:

• selectively removing portions of a substrate, thereby forming emitters, said substrate comprising a surface and a dopant comprising at least one of arsenic, phosphorous, and boron, said dopant substantially covers said surface and forms a concentration gradient in said substrate, said selective removal comprising etching, wherein said gradient decreases with depth into said substrate, said etching having a rate which decreases as the gradient decreases;
• patterning said substrate, said pattern being formed with a mask, said mask comprising a photoresist/silicon nitride/silicon oxide sandwich;
• and
• oxidizing said substrate, said substrate comprising silicon.

A process for fabricating an emitter, said process comprising the following steps of:

• providing a substrate having a substantially continuous face and a depth extending away from said face;
• applying a dopant substantially continuously across said face to form a dopant concentration gradient within said substrate progressively extending away from said face along said depth;
• patterning said substrate by positioning a mask over said face, thereby partitioning said face into an unmasked portion and a masked portion;
• selectively removing said substrate underlying said unmasked portion of said face, thereby retaining a substrate protuberance underlying said masked portion of said face, wherein said substrate protuberance has a base and an apex of substantially the same width, said width corresponding to the width of said mask;
• and
• sharpening said apex of said protuberance into a point or an edge by removing a portion of said apex, thereby defining an emitter, wherein said sharpening comprises oxidizing a portion of said protuberance and removing said oxidized portion.