Studies of field emission from bias-grown diamond thin films
- Materials Science and Chemistry Divisions, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Materials Science Department, Northwestern University, Evanston, Illinois 60208 (United States)
We have investigated the field emission properties of diamond films grown under substrate bias conditions in a microwave plasma chemical vapor deposition system, with a substrate temperature of 800thinsp{degree}C, microwave power of 600 W, and a total pressure of 11 Torr. One group of films was grown with a substrate bias of {minus}100 V in gas mixtures of 1{percent} N{sub 2} and 1{percent}{endash}20{percent} CH{sub 4} in H{sub 2}, while a second group of films was grown with a substrate bias ranging from +100 to {minus}150 V in a gas mixture of 1{percent}N{sub 2}{endash}10{percent}CH{sub 4}{endash}89{percent}H{sub 2}. The field emission performance in terms of threshold field and emission current improved considerably as a function of increasing CH{sub 4} concentration and negative bias voltage. Ultraviolet Raman analysis showed that the field emission enhancement resulting from an increase in CH{sub 4} concentration from 1{percent} to 5{percent} correlates with a decrease in the sp{sup 3} bonding character in the diamond film. The dependence of field emission on negative bias voltage appears to be correlated with ion bombardment-induced damage in the film during growth. The scanning electron microscopy image of the film grown with {minus}150 V bias showed: smaller surface topographic features as compared to films grown under 0 and +100 V bias. The film grown with a bias of {minus}150 V showed the lowest threshold field ({approximately}2.0 V/{mu}m) corresponding to an emission current density of 12.7 {mu}A/cm{sup 2}. {ital J} vs E{sub 0} measurements across a length of 40 mm over the film showed a uniform threshold field (2.0{plus_minus}0.55 V/{mu}m). The film grown with a positive bias (+100 V) showed a relatively poor field emission performance. {copyright} {ital 1999 American Vacuum Society.}
- OSTI ID:
- 347057
- Report Number(s):
- CONF-980797--
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 2 Vol. 17; ISSN 0734-211X; ISSN JVTBD9
- Country of Publication:
- United States
- Language:
- English
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