Field emitter structure and fabrication process providing passageways for venting of outgassed materials from active electronic area

A process for fabricating a field emitter structure, comprising the steps of:

• (a) forming a plurality of upstanding, electrically conductive, pointed field emitters on a surface of an electrically conductive base in an arrangement of rows and columns such that the spacing between adjacent columns is smaller than the spacing between adjacent rows;
• and
• (b) forming electrode means supported above said surface, portions of the electrode means supported above said surface, portions of the electrode means adjacent to the points of the field emitters being separated therefrom by open spaces respectively, and passageway means which interconnect said open spaces;
• step (b) including the substeps of:
• (c) forming an electrically insulative layer on said surface covering the field emitters;
• (d) forming the electrode means as an electrically conductive layer on the insulative layer;
• (e) forming holes through the conductive layer aligned with the points of the field emitters respectively;
• and
• (f) forming holes in the insulative layer through said holes in the conductive layer respectively;
• said holes in the insulative layer exposing the points of the field emitters and constituting at least part of said open spaces in combination with said holes in the conductive layer respectively;
• said holes in the insulative layer being formed such as to undercut said holes in the conductive layer sufficiently to merge together only between adjacent columns and form channels which constitute at least part of the passageway means.