Investigation of the Working Parameters of a Single Magnetron of a Multiple Ion Cluster Source: Determination of the Relative Influence of the Parameters on the Size and Density of Nanoparticles

Multiple Ion Cluster Source (MICS) is the new optimized route of a standard technique based on a sputtering gas aggregation source, the Ion Cluster Source. The single magnetron used in the standard Ion Cluster Source is replaced by three magnetrons inside the aggregation zone, and they are controlled individually in order to fabricate nanoparticles with the desired and tunable chemical composition. Apart from the working parameters of each magnetron, it is also reported that the relation between the working parameters of individual magnetrons is of prime importance for the control of both the size and density of the nanoparticles. The influences of fluxes of the sputtering gas applied to each magnetron, the total gas flux in the aggregation zone, the position in the aggregation zone of Ag magnetron, and the relative position of the magnetrons in the aggregation zone have been studied through the operation of one of the magnetrons loaded with a silver target. 1. Introduction The technique of gas aggregation source is at the forefront of physical methods for the fabrication of nanoparticles (NPs) due to their industrial applications and importance in fundamental research. The fabrication of NPs using this method is based on the formation of a vapor made of elements that aggregate in order to synthesize the desired NPs. Among the different gas aggregation sources, we will focus on the one based on sputtering process due to its efficiency in the fabrication of NPs and to its ability to be used in combination with a quadrupole mass filter thanks to the fact that about 80% of the formed NPs are charged [1–4]. The standard ICS is composed by a single 2-inch diameter magnetron that generates ions of a given material that aggregate in the so-called aggregation zone. The working parameters allow to control the size of the fabricated nanoparticles: (i) the power applied to the magnetron, (ii) the flux of sputtering gas (usually argon), (iii) the aggregation length (distance between the magnetron and the exit slit of the aggregation zone), (iv) the flux of an additional gas, (usually helium), and (v) the aperture size between the aggregation zone and the deposition chamber where the NPs are collected over the desired surface. The flux of clusters or NPs that exit the ICS through the aperture is controlled by the deposition time. With this technique, the chemical composition of the NPs depends on the chemical composition of the target that is placed in the magnetron. It can be operated in ultrahigh vacuum (UHV) or vacuum conditions. Hence, the chemical purity of the