Fk. Urban et al., STUDY OF ZINC THIN-FILMS FORMED USING LARGE CLUSTERS IN THE IONIZED CLUSTER BEAM DEPOSITION TECHNIQUE, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 11(5), 1993, pp. 1916-1920
Ionized cluster beam (ICB) deposition uses a beam of ionized, accelera
ted atom clusters to grow thin films. It has been shown that in ICB ef
forts prior to late 1991, significant numbers of large clusters were n
ot present in depositing beams. Since that time, formation of such lar
ge clusters of zinc by homogeneous nucleation has been demonstrated by
Gspann using radiation crucible heating and pulsed ionizer time of fl
ight cluster size measurement and in our laboratory using electron bom
bardment heating and deflected deposition cluster measurement. Crucibl
e pressure was increased from 2 to over 1000 Torr and a converging-div
erging nozzle 18 mm long and 0.4 mm in diameter at the throat was used
in place of the older 1 mm X 1 mm nozzles. Increasing source pressure
from 2.8 to 11.3 atm (280-1130 kPa) is accompanied by an increase in
peak average cluster size from a few hundred to over 2000 atoms/cluste
r. Surface roughness of cluster formed films increases with increasing
incident cluster energy using a cluster beam peaking at approximately
2200 atoms/cluster in average size for cluster energies from thermal
to approximately thermal plus 700 eV.