Balanced Magnetron Sputtering System Research Articles

Optical monitoring of DC/RF plasma sputtering for copper oxide film growth at low temperature

DC/RF plasma sputtering process for the growth of copper oxide thin film was studied by optical emission spectroscopy. The films were produced by a balanced magnetron sputtering system nearly at room temperature. The influence of applied power in DC and RF mode and Ar/O2 flow ratio on the film properties was investigated as well as their relationship to the plasma species and the main chemical reactions during the film growth. It was found that the concentration of active species in the plasma and their abundance ratio is very effective in the reactions related to the film growth process and the properties of the deposited film. It was shown that copper oxide film with CuO phase owing low energy band gap can be synthesized at low temperatures by controlling the ionization rate, the energy of the active species, the film growth rate, and finally the relative concentration of copper to oxygen species in the plasma. CuO thin films (Eg=1.28 eV) were achieved in DC mode at the lowest applied power (50 W) and in the lowest Ar/O2 flow ratio (2/1). This oxide phase was also observed for two both the synthesized films in RF mode, at 50 W (Eg=1.39 eV) and 100 W (Eg=1.23 eV) in an Ar/O2 flow ratio of 2/1.

Selective bias deposition of CuO thin film on unpolished Si wafer

In order to enhance the performances of CuO-based surface-sensitive materials and devices, one feasible scheme is depositing CuO thin films on textured Si wafers to enlarge the specific surface area. In this work, the bias deposition of CuO thin film on unpolished Si wafer was carried out in a RF balanced magnetron sputtering system. The as-achieved CuO thin film was further characterized with scanning electron microscope, powder x-ray diffractometer and ultraviolet-visible spectrophotometer. It was found that the CuO thin film shows a pyramid-textured film morphology consisting of composite structures: a loose and porous thinner film at the bottom of bevel, a dense and compact thicker film at the top of bevel and on the underside, and many nanosheets standing on the film surface. The tip charging effect and bevel influence were discussed to reveal the selective deposition mechanism of CuO thin film on the unpolished Si wafer. It was also demonstrated that the unpolished rough Si wafer surface seems more suitable for the crystallization of CuO along (002) orientation rather than (111) orientation. Meanwhile, the CuO thin film on unpolished Si wafer exhibits the strongest absorption at the wavelength of ∼554 nm and a band gap of 1.94 eV, both of which show redshift relative to those of CuO thin film on polished Si wafer.

Cu2O porous nanostructured films fabricated by positive bias sputtering deposition

In this work, the authors fabricated Cu2O porous nanostructured films (PNFs) on glass slide substrates by the newly developed positive bias deposition approach in a balanced magnetron sputtering (MS) system. It was found that the surface morphology, crystal structure and optical property of the as-deposited products were greatly dependent on the applied positive substrate bias. In particular, when the substrate was biased at +50 and +150 V, both of the as-prepared Cu2O PNFs exhibited a unique triangular pyramids-like structure with obvious edges and corners and little gluing, a preferred orientation of (111) and a blue shift of energy band gap at 2.35 eV. Quantitative calculation results indicated that the traditional bombardment effects of electrons and sputtering argon ions were both negligible during the bias deposition in the balanced MS system. Instead, a new model of tip charging effect was further proposed to account for the controllable formation of PNFs by the balanced bias sputtering deposition.

Anatase and rutile TiO2 films deposited by arc-free deep oscillation magnetron sputtering

Phase control of TiO2 films at low deposition temperatures is important for many applications. In this study, nanocrystalline TiO2 films were synthesized on glass and steel substrates in a balanced magnetron sputtering system using the new deep oscillation magnetron sputtering (DOMS) and pulsed dc magnetron sputtering (PDCMS) techniques. A virtually arc-free high-power pulsed magnetron sputtering process for TiO2 reactive sputtering was observed for DOMS. No external substrate bias and heating were used for the depositions. For the DOMS TiO2 depositions, different peak target currents (powers) were used. The crystal phase and microstructure of the TiO2 films were characterized and compared. It was found that the TiO2 films deposited by PDCMS exhibited a complete anatase phase. The TiO2 films deposited by DOMS at a low target peak current (e.g. 50 A) also contained mainly the anatase phase. Nevertheless, an increase in the peak target current for the DOMS deposition promoted the formation of the rutile phase, increased the density and decreased the grain size of the TiO2 films. A complete rutile phase was obtained for the TiO2 film deposited by DOMS at a high target peak current (200 A). The mechanical and optical properties of the anatase and rutile TiO2 films were also studied and compared.

A comparative study of CrAlN films synthesized by dc and pulsed dc reactive magnetron facing target sputtering system with different pulse frequencies

CrAlN films were prepared using a balanced magnetron sputtering system operated in dc and pulsed condition (with different pulse frequencies), and their phase composition were then determined through XRD analysis. In order to investigate the relationship between the mechanical properties and microstructure of the films, hardness measurements were taken using a nanoindentation system. All films exhibited NaCl-type CrN structure in both dc and pulsed conditions. Plastic hardness, H pl, of the films ranged between 15 to 36 GPa. Pulsed prepared CrAlN films showed higher hardness, higher internal stress values, and smaller grain sizes than dc prepared CrAlN film. Moreover, plastic hardness and internal stress of pulsed prepared CrAlN films increased on increasing pulse frequency.

Influence of total gas pressure on the microstructure and properties of CrAlN films deposited by a pulsed DC balanced magnetron sputtering system

CrAlN films have been prepared using a pulsed DC reactive sputtering system. The effects of N 2/Ar ratio and pulse width on the film's structure and properties have been investigated. The total sputtering pressure decreased with increased N 2/Ar ratio. All CrAlN films showed NaCl-type CrN structure, while mixed structures of wurtzite-type Cr 2N, wurtzite-type AlN and NaCl-type CrN phases formed in the films produced under lower sputtering pressure and higher pulse width. Increasing the sputtering pressure resulted in a decrease in the films internal stress. Moreover, the plastic hardness of the films prepared under different pulse widths was higher at the lower sputtering pressure.

Oxidation Resistance of CrAlN Films with Different Microstructures Prepared by Pulsed DC Balanced Magnetron Sputtering System

CrAIN films were prepared using a pulsed DC balanced reactive sputtering system under different N 2 /Ar ratios and pulse widths. We investigated the oxidation resistance of two CrAIN films with different microstructures; i) with a fcc-CrN structure, lower internal stress and moderate hardness, and ii) with a mixed structure of hcp-AlN and hcp-Cr 2 N phases, higher internal stress and super high hardness of 41 GPa. The CrAlN film (i) having the single fcc-CrN structure showed good oxidation resistance up to 900°C. The plastic hardness of this film increased to a maximum of 38.5 GPa at 900°C. In contrast, the CrAIN film (ii) with the mixed structure of hcp-AlN and hcp-Cr 2 N phases was stable up to 800°C. The plastic hardness of this film decreased gradually with annealing.

Nanostructured CrAlN Films Prepared at Different Pulse Widths by Pulsed DC Reactive Sputtering in Facing Target Type System

CrAlN films have been prepared using a pulsed DC reactive sputtering in FTS system with Cr/Al alloy (¼ 50=50 at%) targets in a mixed atmosphere of Ar and N2. The effects of pulse width on the film structure and properties have been investigated. XRD analyses were carried out to determine the phases and texture of the films. Transmission electron microscopy studies were carried out for selected films. In order to investigate the relationship between the mechanical properties and microstructure of the films, the hardness was measured by a nanoindentation system. Films prepared at lower pulse widths, exhibited fcc-CrN structure. In contrast, films that were prepared at higher pulse widths showed a mixed structure of hcp-AlN, hcp-Cr2N and a small amount of fcc-CrN phases. Plastic hardness, Hpl, of the films ranged between 32 to 41 GPa while the Young’s modulus, EIT, of the films ranged from 320 to 340 GPa. Increasing the pulse width also resulted in an increase in the film’s internal stress. In addition, the grain size of the samples decreased with increasing pulse width. Consequently, the film deposited at higher pulse width exhibited high hardness of 41 GPa, H 3 =E 2 ratio of � 0:6 and relatively lower internal stress of � 3:5 Gpa. These results indicated that changing the pulse width can strongly affect structure and properties of CrAlN films, resulting in a good combination of mechanical and tribological properties, under proper conditions in a pulsed DC Balanced Magnetron Sputtering system. [doi:10.2320/matertrans.MER2008249]

TiN–AlN nanomultilayer films for microdrilling and machining

In this study, TiN–AlN nanomultilayer films were prepared using a new sputtering technique, which was designed and manufactured on the basis of a newly developed technology, i.e. high speed reactive plasma aided physical vapour deposition. This technique featured both an unbalanced magnetron sputtering system and a balanced magnetron sputtering system. The former was employed to deposit the AlN film, and the latter to deposit the TiN film. The aim of this study was primarily to obtain, through controlled deposition conditions, a group of TiN–AlN nanomultilayer films and then to investigate the influence of various sequences on their fundamental properties and wear behaviour. Finally, two sets of field tests, microdrilling and machining, were conducted in order to determine the feasibility of applying the multilayers in production machining situations. The results revealed that, via control of the deposition parameters, TiN–AlN nanomultilayer films ranging from 2·4 to 67·6 nm could be obtained. At a periodicity of ≥3·6 nm, the multilayers had extremely high hardness, and excellent adhesion and wear performance. Field testing confirmed that the nanomultilayers could provide very significant improvement in actual machining performance, as compared with the traditional single layer TiN films.

Tribology and oxidation behavior of TiN/AlN nano-multilayer films

In this study, a series of TiN/AlN nano-multilayer films were prepared using a new sputtering setup, which features a medium frequency (MF) twin unbalanced magnetron sputtering system (UBMS) and a DC balanced magnetron sputtering system (BMS). The MF (6.78 MHz) twin UBMS, which is a modification of single RF power source system, is a special design of this deposition machine. The UBMS was employed to deposit the AlN film, and the BMS the TiN film. The aim of this study was to obtain, through controlling the deposition conditions, a group of TiN/AlN nano-multilayer films with various periods ( λ). Then a series of experiments were conducted to understand their wear and oxidation properties. The results revealed that through controlling of the deposition parameters, the TiN/AlN nano-multilayer films with λ ranging from 2.4 to 67.6 nm were obtained. At λ≦3.6 nm, the nano-multilayers had extremely high hardness and excellent adhesion. The oxidation tests found that the multilayers had obviously better anti-oxidation property, as compared with the single-layer TiN film. The high hardness and good oxidation resistance contributed to very good wear performance of the TiN/AlN nano-multilayer films.

Effect of periods on wear performance of TiN/AlN superlattice films

In this study, the TiN/AlN superlattice films were prepared using a newly developed high-rate reactive sputtering set-up, which featured an unbalanced and a balanced magnetron sputtering system. The former was employed to deposit the A1N film, and the latter the TiN film. The aim of this study was to obtain, through controlling the deposition conditions, a group of TiN/AlN superlattice films with various periods, and then to investigate the influence of periods on their fundamental properties and wear behavior. The results revealed that the TiN/AlN superlattice films with periods ranging from 2.4 to 67.6 nm were obtained. At periods ≦ 3.6 nm, the films had extremely high hardness, excellent adhesion and wear performance, as compared with the traditional single-layer TiN film.

On the tribology and micro-drilling performance of TiN/AlN nanolayer coatings

In this study, the TiN/AlN nanolayer coatings were prepared using a new sputtering setup, which was designed and manufactured on the basis of a newly developed technology – the high-rate reactive sputtering process. This setup featured an unbalanced magnetron sputtering system and a balanced magnetron sputtering system. The former was employed to deposit the AlN film, and the latter the TiN film. Through controlling the deposition conditions, a group of TiN/AlN nanolayer coatings with various periods was obtained. The aim of this study was to investigate the influence of periods of the nanolayer coatings on their fundamental mechanical properties and wear behavior first. And then, a field test was conducted to approve the feasibility of applying the nanolayer coatings on micro-drills for circuit board hole-drilling. The results revealed that through controlling of the deposition parameters, the TiN/AlN nanolayer coatings with periods ranging from 2.4 to 67.6 nm were obtained. At periods ≤3.6 nm, the films had extremely high hardness, excellent adhesion and wear performance, as compared with a TiN standard coating. The field test confirmed that the nanolayer coatings could provide a lot enhancement in micro-drilling performance.

On the micro-drilling and turning performance of TiN/AlN nano-multilayer films

Abstract In this study, the TiN/AlN nano-multilayer films were prepared using a new sputtering set-up, that was designed and manufactured on the basis of a newly developed technology—the high-rate reactive sputtering deposition process. This set-up featured an unbalanced magnetron sputtering system and a balanced magnetron sputtering system. The former was employed to deposit the AlN film, and the latter the TiN film. The aim of this study was to obtain, through controlled deposition conditions, a group of TiN/AlN nano-multilayer films with various periods (TiN/AlN twin-layer thickness) first, and then to investigate the influence of periods on their fundamental properties and wear behavior. Finally, two sets of field tests, micro-drilling and turning, were conducted in order to understand the feasibility of applying the multilayers on actual machining. The results revealed that through controlling of the deposition parameters, the TiN/AlN nano-multilayer films with periods ranging from 2.4 to 67.6 nm were obtained. At periods ≦3.6 nm, the multilayers had extremely high hardness, excellent adhesion and wear performance. The field tests confirmed the nano-multilayers could provide a significant improvement in actual machining performance, as compared with the traditional single-layer TiN film.

On the tribology and micro-drilling performance of TiN/AlN nanolayer coatings

Abstract In this study, the TiN/AlN nanolayer coatings were prepared using a new sputtering setup, which was designed and manufactured on the basis of a newly developed technology – the high-rate reactive sputtering process. This setup featured an unbalanced magnetron sputtering system and a balanced magnetron sputtering system. The former was employed to deposit the AlN film, and the latter the TiN film. Through controlling the deposition conditions, a group of TiN/AlN nanolayer coatings with various periods was obtained. The aim of this study was to investigate the influence of periods of the nanolayer coatings on their fundamental mechanical properties and wear behavior first. And then, a field test was conducted to approve the feasibility of applying the nanolayer coatings on micro-drills for circuit board hole-drilling. The results revealed that through controlling of the deposition parameters, the TiN/AlN nanolayer coatings with periods ranging from 2.4 to 67.6 nm were obtained. At periods ≤3.6 nm, the films had extremely high hardness, excellent adhesion and wear performance, as compared with a TiN standard coating. The field test confirmed that the nanolayer coatings could provide a lot enhancement in micro-drilling performance.

Thermal power at a substrate during ZnO:Al thin film deposition in a planar magnetron sputtering system

In a balanced magnetron sputtering system the thermal power at a substrate has been determined from the temperature change of the substrate when the plasma is switched on. Using the temperature as a function of the potential of a probe, the calorimeter has been calibrated absolutely. A heat input equivalent of about 10 eV per electron has been determined for a dc discharge. The results for the total thermal power at the substrate are compared with values published by other groups for similar discharge systems. The contributions of different kinds of particles are discussed. For the dc discharge at a discharge power of 50 W and a pressure of 0.8 Pa, a thermal power of 15.6 mW cm−2 has been found which is mainly produced by particles other than the plasma ions. It can be concluded from the increase of the thermal power with decreasing pressure that bombardment by particles originating from the target is the main source of the substrate heating. In an rf discharge the ion energy is two times and the flux density is nearly three times higher than in a dc discharge. Here the dependence of the thermal power on pressure is only weak and mainly the plasma ions transport the power to the substrate.