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Author: Ali Kosari Mehr
Devised by Takagi in the 1970s, ionized-cluster beam deposition (ICBD) is a method developed from the ion plating method. The deposition process of this method is comprised of four steps: First, evaporation of atoms from a closed source occurs by means of a nozzle. Second, the atoms form clusters, having cooled via expansion in the nozzle – the number of atoms in each cluster can range from a few hundred atoms to a thousand atoms. Third, passing through a plasma region, the formed clusters are ionized. Fourth, the ionized clusters are accelerated towards the substrate. In this connection, in spite of the fact that the accelerated clusters can have energy in the range of kilo-electron volts, the average energy of the atoms in these clusters is within the range of 0.2 electron volts to several electron volts. Therefore, the substrate surface is not likely to be damaged by the adatoms owing to their relatively low energy [1].
Mainly, it is complex to examine the characteristics of the films formed by an ion-assisted deposition method such as ion plating and ion beam sputtering. However, one can simply estimate the effect of deposition parameters upon film formation in the ionized-cluster beam deposition method by means of measuring deposition conditions; this is due to a relatively high-vacuum region in which films are deposited. Practically, there are six significant factors affecting the quality of the films:
