INVESTIGATIONS OF IN-SITU CARBON COATING ON FIELD-EMITTER ARRAYS

The effect of two types of carbon coating on molybdenum (Mo) tips in ' Spindt'-type microfabricated field-emitter arrays has been investigate d. The first serf of carbon coating was deposited by dissociating acet ylene gas in situ to produce an amorphous film. This deposition result ed in a permanent increase in the emission current at constant applied field of about 20%. The influence of thermal treatment before, during and after the coating procedure was also studied Stability measuremen ts demonstrated that the stability of the emission current was increas ed by the coating process. The second part of the experiments was carr ied out with the field-emitter array being set in an arrangement that allows C2H2 plasma production at a pressure of 1 torr, and which depos its a diamond-like film on the tips. Subjecting the cathodes to this p lasma for short periods (< 1 min) enhanced the emission current and it s stability. Longer periods of treatment (> 3 min), where heavy carbon deposition occurred, resulted in current instabilities.