Prospects for reducing arc damage in RF-compatible FEAs

A primary failure and degradation mechanism in FEAs is arc damage. Our measurements show that arc damage is reduced by placing resistance in series with FEAs, but appears to remain the dominant failure mechanism. Once ignited, an arc can potentially dissipate most of the energy stored in the charged capacitance of the FEA, regardless of how well protected the FEA is. Simple calculations show that the energy stored in a state-of-the-art low capacitance FEA is more than enough to melt sufficient material to ruin a tip or form a short between a tip and the gate. In order to produce more uniform emission for display applications, resistances are typically incorporated into the array in series with each tip. Arc damage has been suppressed in these FEAs, allowing them to be used in poor vacuums. The resistance produces a significant RC time constant, limiting the frequency at which the gate-tip voltage can be modulated. However, the value of the resistance appropriate for display applications may be much larger than required to reduce arc damage. Similarly, the capacitance in series with the resistor can be made very small. Thus it may be possible to use integrated resistance to limit arc damage while maintaining RF modulation compatibility