Pulsed Magnetron Sputtering Process Research Articles

Advanced Coatings Through Pulsed Magnetron Sputtering

Pulsed magnetron sputtering (PMS) has become established as the process of choice for the deposition of dielectric materials for many applications. The process is attractive because it offers stable arc free operating conditions during the deposition of, for example, functional films on architectural and automotive glass, or antireflective/antistatic coatings on displays. Recent studies have shown that pulsing the magnetron discharge also leads to hotter and more energetic plasmas in comparison with continuous dc discharges, with increased ion energy fluxes delivered to the substrate. As such, the PMS process offers benefits in the deposition of a wide range of materials. The present paper describes three examples where PMS has led to either significant enhancement in film properties or enhanced process flexibility: in low friction titanium nitride coatings, in Al doped zinc oxide transparent conductive oxide coatings sputtered directly from powder targets and in thin film photovoltaic devices based on copper (indium/gallium) diselenide. These examples demonstrate the versatility of PMS and open up new opportunities for the production of advanced coatings using this technique. SE/499

Requirements of power supply parameters for high-power pulsed magnetron sputtering

In the last few years, a new sputter process technology called pulsed magnetron sputtering (PMS) has been developed and has become relevant for industrial applications of large-area coating. The combination of a pulsed power supply and a dual magnetron sputter (DMS) system enables the deposition of insulating layers, such as Al 2O 3, SiO 2, ZnO and SnO 2, with high rates as DC sputtering. The pulsed magnetron sputtering process in conjunction with high power density requires intelligent process and arc management. The interactions between process control and the dynamics of the power supply are described by means of the deposition of tin oxide and zinc oxide. The meaning of process instabilities in the arcs were analyzed with V– I curves. A high-speed camera was used to observe the dual magnetron sputter system during arcing. The dynamics of the coating system were characterized using the temporal behavior of the oxygen partial pressure, which was measured with a lambda probe. The result of the optimization of the system power-supply sputter source is a deposition process with long-term stability.

Characterisation studies of the pulsed dual cathode magnetron sputtering process for oxide films

Pulsed magnetron sputtering has become the leading industrial production process for large area thin film deposition due to its versatility, low environmental impact and ability to provide uniform coatings across large substrate areas. Such applications commonly employ oxides, including silica (SiO 2), alumna (Al 2O 3) and titania (TiO 2). Although all of these materials can be produced by reactive DC-magnetron sputtering, until recently the deposition process was highly problematic. The industrial exploitation of the pulsing process is impeded by the fact that, during long-term deposition runs, eventually all surfaces will be covered with the insulator. Once the chamber and anode are covered with insulating material, there can be no average (DC) current flowing to the power supply leads. Moreover, if the anode/chamber becomes covered with the dielectric film it will cease to operate as an effective ground (anode). A more viable approach is to use two magnetrons in a dual bipolar arrangement (dual cathode). In this arrangement each magnetron acts alternatively as an anode and a cathode. The broad aim of this study is to investigate the inter-relationship between ‘global’ parameters, pulse parameters, plasma parameters and in particular, film properties in relation to the dual cathode system. The spatial distribution of measured parameters will be considered. This paper describes the production of Al 2O 3 films by dual cathode unbalanced reactive magnetron sputtering, in particular, the effects of spatial distribution and pulse frequency on coating properties. In general, it was observed that, once hard arcs have been removed, all coating structures, coating surfaces and hardness show little variation. However, more variation was observed in critical loads during scratch adhesion testing for coatings deposited at different pulse frequencies.

Reactive pulsed magnetron sputtering process for alumina films

The pulsed magnetron sputtering (PMS) process is now among the leading techniques for the deposition of oxide films. In particular, the use of pulsed dc power has transformed the deposition of dielectric materials, such as alumina. The periodic target voltage reversals during the PMS process effectively discharge poisoned regions on the target. This significantly reduces the occurrence of arc events at the target and stabilizes the deposition process. Many researchers have now shown that pulsed dc reactive magnetron sputtering can be routinely used to produce fully dense, defect-free oxide films. Despite the success of the PMS process, few detailed studies have been carried out on the role played by parameters such as pulse frequency, duty cycle, and reverse voltage in the deposition process. In this study, therefore, alumina films were deposited by reactive pulsed dc magnetron sputtering. Operating conditions were systematically varied and the deposition process monitored throughout. The aim was to investigate the influence of the pulse parameters on the deposition process, and the interrelationships between the occurrence of arc events and the parameters chosen. As a result of this investigation, optimum conditions for the production of high-quality alumina films under hard arc-free conditions were also identified.

The influence of pulsed magnetron sputtering on topography and crystallinity of TiO 2 films on glass

The pulsed magnetron sputtering process is a way of increasing the number of sputterable materials in comparison to the conventionally used DC process, to enhance the stability and efficiency of the sputtering process and, not least, to obtain films with ‘new’ properties. The last mentioned effect means that the properties can be changed, e.g. the optical and mechanical properties. These are investigated by various analytical methods, especially by atomic force microscopy (AFM) and X-ray diffraction (XRD) to characterize the topography and the crystalline phase of the layers. From the experimental results and from literature results we find a good conformity with the condensation model given by Löb [1]. We conclude that the substrate temperature and the energy of the particles impinging on the substrate are the relevant parameters which determine the film structure. The nucleation of the rutile phase is favoured by the pulse sputter technique. Pulse sputtered and DC sputtered TiO 2 layers are compared with regards to optical, mechanical and structural properties.