Emission statistics for Si and HfC emitter arrays after residual gas exposure

Field emission arrays (FEAs) comprising 100 Si or HfC coated Si emitters have been fabricated. The FEAs emission properties were measured in ultra high vacuum conditions and after being subject to Ar and O 2 residual gases with partial pressures in the range 10 − 6 to 10 − 4 Pa . The influence of re...

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Veröffentlicht in:Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 2005-03, Vol.23 (2), p.707-717
Hauptverfasser: Nicolaescu, D., Nagao, M., Sato, T., Filip, V., Kanemaru, S., Itoh, J.
Format: Artikel
Sprache:eng
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Zusammenfassung:Field emission arrays (FEAs) comprising 100 Si or HfC coated Si emitters have been fabricated. The FEAs emission properties were measured in ultra high vacuum conditions and after being subject to Ar and O 2 residual gases with partial pressures in the range 10 − 6 to 10 − 4 Pa . The influence of residual gases on the FEAs field emission properties has been comparatively assessed using the model parameter extraction method. The array field emission model uses equations that describe the electron emission current from individual emitters of given radius R and work function ϕ together with nonuniform distribution functions giving the dispersion of these parameters within the array. A simplified relationship for the array emission current depending on a single integral instead of a double one has been derived. A nonlinear extraction algorithm using partial derivatives of the objective function is used, which gives fast and accurate results. Both Si and HfC emitters exhibit (to a different degree) tightening of the radius distribution with time and more uniform emission, when exposed to O 2 residual gas. The current degradation of Si and HfC arrays, when exposed to Ar residual gas, is mostly associated with the work function increase. HfC emitters have higher emission currents, lower noise level, and better stability of the emission than Si emitters. These properties are discussed in terms of the array parameter statistics.
ISSN:0734-211X
1071-1023
1520-8567
2327-9877
DOI:10.1116/1.1864058