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The discharge voltage was measured for 15 different metallic target materials at constant current before and after plasma oxidation in order to understand its behavior during reactive magnetron sputtering. Plasma oxidation of the target surface was achieved by sputtering the target in pure oxygen. The discharge voltage measured in pure argon is characteristic for each kind of metallic target and is related to the ion induced secondary electron emission (ISEE) coefficient of the target material. Based on this relation a value for the ISEE coefficient of the oxidized target surface can be calculated. Two distinct groups can be discerned: for one group the ISEE coefficient of the oxidized target surface is larger than the ISEE coefficient of the metal, while the opposite behavior is noticed for the second group. This difference seems to find its origin in the reduction behavior of the oxides under ion bombardment, since the ISEE coefficient of the oxide can be related to the simulated degree of reduction of the oxide. It is shown that the ISEE coefficient of the reduced oxides decreases with increasing oxygen content in the target. This is confirmed experimentally by sputtering in pure argon reduced titanium oxide targets with a known composition.

A Monte Carlo simulation of the metal flux from a small scale rotating cylindrical magnetron is presented. The model describes the sputtered particles trajectories through the gas in a user definable 3D set-up. The ejection positions of the sputtered particles are generated according to the simulated ion current density on the target. The thermal motion of the background gas is included, with collisions modelled based on either quantum chemical or screened Coulomb interaction potentials. Experimental characterization of the metal flux was performed for Cu, Al and Ti targets at a range of argon pressures (0.3–1 Pa) by measuring deposition rate distributions. A comparison with preliminary simulations showed the importance of a correct description of the nascent angular distribution of the sputtered particles. Therefore, this distribution was not considered as given by sputter simulation or analytical formula, but was instead reconstructed from the low pressure experimental deposition profiles. The typical heart-like shaped emission observed at low energy sputtering was found and a comparison was made with results from binary collision approximation modelling. The spatial, pressure and material dependence of the metal flux in the chamber was then simulated and found to be in good agreement with the experiment.

The growth of reactively sputtered TiN films is discussed. First, an overview of the existing models in the literature that describe the development of the orientation and microstructure is given. Then, these models are critically confronted with the results of experiments published in the literature and performed by the authors. The latter experiments focus especially on the determination of the energy flux and atomic N/Ti flux towards the substrate and lead to the conclusion that these fluxes towards the substrate play a key role in the growth of the TiN films. This relation between these fluxes and the microstructure of the TiN films gives further evidence to the previously published extended structure zone model.

Sputter deposition is a widely used technique to deposit thin films on substrates. The technique is based upon ion bombardment of a source material, the target. Ion bombardment results in a vapor due to a purely physical process, i.e. the sputtering of the target material. Hence, this technique is part of the class of physical vapor deposition techniques, which includes, for example, thermal evaporation and pulsed laser deposition. The most common approach for growing thin films by sputter deposition is the use of a magnetron source in which positive ions present in the plasma of a magnetically enhanced glow discharge bombard the target. This popular technique forms the focus of this chapter. The target can be powered in different ways, ranging from dc for conductive targets, to rf for nonconductive targets, to a variety of different ways of applying current and/or voltage pulses to the target. Since sputtering is a purely physical process, adding chemistry to, for example, deposit a compound layer must be done ad hoc through the addition of a reactive gas to the plasma, i.e. reactive sputtering. The undesirable reaction of the reactive gas with the target material results in a non-linear behavior of the deposition parameters as a function of the reactive gas flow. To model this behavior, the fluxes of the various species towards the target must be determined. However, equally important are the fluxes of species incident at the substrate because they not only influence the reactive sputter deposition process, but also control the growth of the desired film. Indeed, the microstructure of magnetron sputter deposited films is defined by the identity of the particles arriving at the substrate, their fluxes and the energy per particle.

Using an analytical model, the effect of reactive ion implantation on the state of the target surface during magnetron sputtering is studied. To describe the substrate condition during reactive sputter deposition, the model uses the well-known Berg model approach. However, the target condition is modelled differently, i.e. besides chemisorption the model includes reactive ion implantation. To test this latter modification, the simulation results are compared with the results of oblique reactive ion beam experiments. The good agreement forms the basis of using the model for reactive magnetron sputtering. It is shown that the well-known hysteresis behaviour of the deposition parameters can be described. Although at first sight the model is comparable to other models, it is shown that the kinetics are clearly different. A good description of the kinetics during reactive magnetron sputtering is essential to model, for example, the reactive sputter process using a rotating cylindrical magnetron.

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