GOLD AND ZINC THIN-FILMS DEPOSITED BY THE IONIZED CLUSTER BEAM TECHNIQUE

Thin film deposition from beams of atom clusters, some of which are io nized and accelerated to the growing surface, was first proposed in 19 72. This idea created interest because it was fundamentally different from other deposition methods and was expected to have unique capabili ties. Development of a suitable cluster source has been difficult, and large clusters of zinc (about 2000 atoms per cluster) have only recen tly been produced. Two source parameters were changed to accomplish th is. The crucible pressure was increased from 2 Torr to over 1000 Torr, and a converging-diverging nozzle 18 mm long and 0.4 mm in diameter a t the throat was used in place of the older nozzle with dimensions of 1 mm x 1 mm. To separate the pressure and nozzle effects, gold thin fi lms are being deposited with the new converging-diverging nozzle. The vapor pressure of gold is much lower than that of zinc at a given temp erature. Cluster size measurements show no significant numbers of gold clusters. The effect of the crucible pressure on the formation of the large cluster is much more significant than that of the nozzle geomet ry. The effects of varying ion energy bombardment on film microstructu re are also evaluated using atomic force microscopy.