ICMCTF2004 Session B2-1: Arc and E-Beam Coatings and Technologies

Wednesday, April 21, 2004 8:30 AM in Room Golden West
Wednesday Morning

Time Period WeM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2004 Schedule

Start Invited? Item
8:30 AM B2-1-1 Structure and Electrical Properties of AlN Thin Films Prepared by High Vacuum Electron Beam Evaporation
M. Zhu, R.K.Y. Fu, P. Chen (City University of Hong Kong); W. Liu, C.L. Lin (Chinese Academcy of Sciences, P.R. China); P.K. Chu (City University of Hong Kong)
Silicon-on-insulator (SOI) microelectronic devices have an inherent self-heating effect which limits the applicability of SOI materials in which high power dissipation is expected. This is a consequence of the low thermal conductivity of the buried oxide layer in conventional SOI devices. In this work, we use an aluminum nitride (AlN) thin film formed by high vacuum electron-beam evaporation as an alterative to the buried silicon dioxide layer. In our experiments, the main vacuum chamber was evacuated to below 10-9 mbar. Initially, one to two monolayers of Al were deposited onto the Si substrate surface to prevent the formation of Si3N4, followed by the introduction of ammonia through a leak valve to maintain the working pressure at 8-10-6 mbar. Under a high vacuum, Al was evaporated by an electron gun to react with ammonia to form AlN. The substrates were maintained at 800°C (sample 1) and room temperature (sample 2) during deposition. X-ray photoelectron spectroscopy (XPS) was used to determine the film composition. Our results show that only sample 1 is AlN, but the chemical composition of sample 2 is almost Al2O3. It indicates that ammonia can only be ionized when the substrate is under a high temperature. Sample 1 was characterized by spreading resistance profile (SRP) and atomic force microscopy (AFM). Experimental results confirm that a good quality AlN film is produced. It has excellent dielectric properties and a smooth surface with a roughness RMS value of 0.3 nm. The surface is good enough for direct wafer bonding. In addition, the current-voltage characteristic was measured using a fabricated metal/AlN/Si structure (MIS device). The AlN film exhibits good insulating properties and its breakdown field is 2 MV/cm. In conclusion, the AlN thin films are successfully fabricated by high vacuum electron beam evaporation with ammonia, and they are appropriate for SOI applications.
8:50 AM B2-1-2 Low-temperature Deposition of Hard Coatings Assisted by Metal Ion Implantation
A.N. Panckow, D. Sladkov (Otto-von-Guericke-University, Germany); Ch. Genzel (Hahn-Meitner-Institut, Germany)
Wear resistant coatings were deposited using a vacuum arc ion-plating technique combined with pulsed plasma surface treatment. Combining the pulsed processes of the bias voltage as well as the metal vapor vacuum arc ion source, the substrate temperature was kept below 160°C. The metal ion source was equipped with a Cr-cathode, a low-frequency ignition system and high voltage supplies for the ion acceleration and plasma shielding, respectively. Physical properties of the coatings, like thickness, hardness and adhesion, were clearly influenced by the metal ion bombardement before and during the deposition process. This will be shown for the example of TiN coated cemented carbide tools modified by Cr ion implantation with an ion acceleration voltage varied up to 40 kV. The findings of nanoindentation measurements are consistent with the results of X-ray stress analysis investigations. The effect of the metal ion implantation process into the surface region of the carbide tools and the growing coatings on the tool life time will be discussed.
9:10 AM Invited B2-1-3 Large Scale Synthesis of Novel Nano-materials using the Submerged Arc Method
M. Chhowalla (Rutgers University)
In this presentation, we will describe an outstandingly simple and inexpensive technique for synthesizing nano-materials. Efficient and cost effective synthesis of nano-materials is essential if they are to be used in applications where large quantities of materials are desired. Such applications include electrodes for fuel cells, super-capacitors and high strength polymer matrix composites. Specifically, fabrication of carbon nanostructures such as nanotubes, nano-onions and single wall nanohorns by arc discharge in deionized water and liquid nitrogen will be presented. The structural properties of the synthesized nano-materials will also be discussed. The submerged arc technique is easily scalable and can readily produce these technologically important novel nano-materials at a rate of several grams per hour.
9:50 AM B2-1-5 Nano-composite Coating Growth using Hybrids of Filtered Cathodic Arc and Other Plasma Sources.
A.A. Voevodin, J.G. Jones, T.C. Back, J.S. Zabinski (Air Force Research Laboratory)

Filtered cathodic arc (FAD) provides a unique opportunity to obtain metal or carbon ion beams with a good control of their energy and flux density. The technique is industrially scalable and the FAD source can be combined at the same deposition chamber with other plasma sources. Such combination is essential for the preparation of advanced nanocomposite coatings. For example, supertough nanocrystalline/amorphous coatings and adaptive chameleon tribological coatings are best produced using hybrid deposition methods, e.g. combining magnetron sputtering and pulsed laser ablation [1-3]. In hybrid processes, it is possible to grow composite materials which individual phases require drastically different deposition conditions. This paper provides examples of hybrids of FAD with magnetron sputtering, pulsed laser deposition, and atomic gas sources. These processes were explored for the production of nanocomposite materials, where metal, carbon, and dichalcogenide phases were combined into the coatings with advanced wear protective and low friction properties. Discussion of the hybrid processes highlights their main advantages for the nanocomposite coating growth.

[1] A. A. Voevodin, S. V. Prasad, J. S. Zabinski, Nanocrystalline carbide / amorphous carbon composites, J.Appl.Phys. 82 (1997) 855-858.

[2] A. A. Voevodin, J. S. Zabinski, Supertough wear resistant coatings with 'chameleon' surface adaptation, Thin Solid Films 370 (2000) 223-231.

[3] A. A. Voevodin, J. J. Hu, T. A. Fitz, J. S. Zabinski, Nanocomposite tribological coatings with "chameleon" friction surface adaptation, J.Vac.Sci.Technol.A 20 (2002) 1434-1444.

10:30 AM Invited B2-1-7 Effects of Cr Contents on Micro-hardness and Microstructure in TiAlN Films Synthesized by AIP Method
T. Yamamoto, H. Hasegawa (Keio University, Japan); K. Yamamoto (Kobe Steel Ltd., Japan); T. Suuzuki (Keio University, Japan)

It is well known that incorporation of Al atoms to TiN and CrN films shows phase transitions from the cubic to hexagonal structure at certain Al amount. In our previous work, the micro-hardness of Ti1-xAlxN changed from 20 GPa to 32 GPa with keeping NaCl structure. Further, the Cr1-xAlxN films showed maximum hardness of 27 GPa with X=0.6, which was similar transition behavior to the case of Ti1-XAlxN films.

The purpose of this study is to obtain maximum solubility of three kinds of metals, Ti, Cr and Al keeping the c-phase. In this study, effects of Cr addition into Ti1-xAlxN films were investigated by measuring changes in lattice parameter.

Ti0.1Cr0.2Al0.7N films were synthesized by the arc ion plating method (AIP) between 400 and 650°C. The micro-hardness of films showed maximum value of 30 GPa at 520°C. The crystal structures changed from the cubic to the mixture phase with cubic and hexagonal structure with increasing deposition temperature. The grain size of Ti0.1Cr0.2Al0.7N at 520°C was approximately 100 nm and indicated by dots in the photographs.

11:10 AM B2-1-9 Influence of the Diameter of an Annular Anode on Plasma Transport Through the Anode of a Vacuum Arc Deposition System
V.N. Zhitomirsky, R.L. Boxman, S Goldsmith (Tel-Aviv University, Israel)

In vacuum arc deposition systems, the depositing plasma is generated at the surface of the cathode, and is often passed through an aperture in the anode on its way to the substrate. In this work, the influence of the aperture diameter on the plasma transport was measured. The plasma source consisted of a conical Cu cathode of 17 mm diam, and an annular Cu anode of D=10, 17, 30, 40 and 50 mm i.d. and 20 mm thick, through which the plasma beam entered into the 160 mm diameter and 500 mm length cylindrical duct. Magnetic coils positioned co-axially with the duct axis produced an approximately axial magnetic field guiding the plasma in the duct. The arc current, Iarc, was in the range of 30-100 A. A 130 mm diam. negatively biased planar disk probe, positioned normal to the duct axis at a distance of 150 mm from the anode exit, was used to measure the ion saturation current, Ip. The ion saturation current to the duct wall, Id, the arc voltage, Varc, and the probe and duct floating potentials with respect to the anode, were measured as functions of D, Iarc, and the axial magnetic field B.

Generally, Ip and Id increased almost linearly with D. Ip as function of Iarc increased almost linearly for D=40 mm, increased and became saturated for D=17 mm, whereas for D=10 mm, Ip first increased up to a maximum value at Iarc=80 A and decreased for larger values of Iarc. Varc increased with D, and for all D, Varc decreased with increasing Iarc. Both probe and chamber floating potentials were negative relative to the anode, and became increasingly negative with increasing D and B. It was shown that the system efficiency Ip/Iarc increased with increasing D, from ~0.8% at D=10 mm to 10% for large D. However, at large D (≥ 50 mm), the probability of the arc extinguishing increased.

11:30 AM B2-1-10 Anode Temperature Distribution and Coating Characteristics in a Hot Refractory Anode Vacuum Arc with an Assymetric Anode
I.I. Beilis, A. Shashurin, A. Nemirovsky, S Goldsmith, R.L. Boxman (Tel-Aviv University, Israel)

The Hot Refractory Anode Vacuum Arc (HRAVA) is a metallic coating plasma source using a conventional water-cooled metal cathode, and an anode made from a non-consumable refractory material. The metallic plasma plume is generated by re-evaporation of cathode material from the anode, which is heated by the arc, vastly reducing the macroparticle contamination from that obtained with conventional cathodic vacuum arc sources. In the present work, an asymmetric anode geometry, intended to control the plasma plume direction, is investigated.

Arcs were sustained between a cylindrical copper cathode and a thermally isolated, 32 mm diameter cylindrical graphite anode whose distal end was cut off at various angles, so that its minimal and maximal lengths L1 and L2 could differ. Anodes with three cut-off angles were investigated: (1) symmetrical anode, L1=L2=30mm (2) L1=25mm, L2=30mm; (3) L1=20mm, L2=30mm. The time dependent anode temperature was measured using high-temperature thermocouples at two points a few mm below the distal surface near the minimal and maximal length points and at one point near the rear surface. Arc currents of 120-225 A were sustained for periods up to 150 s with distances of 9-18 mm between the electrodes.

The measured anode temperature increased with arc time and approached a steady-state value. The anode temperature increased linearly with arc current. The steady state temperature of the asymmetric anodes was approximately 100C greater, and rose at a faster rate, than that of the symmetric anodes. The temperature measured near L1 reached approximately 1200, 1300 and 1400K for anodes (1), (2) and (3), respectively, 30s after arc ignition for Iarc=175 A and electrode distance 18 mm. The maximal anode temperature near L2 in the asymmetric anodes decreased by about 100-150o when the electrode separation was increase from 9 to 18mm (175 A), while the temperature at near L1 and the rear surface varied only weakly.

11:50 AM B2-1-11 Catodic Arc PVD Multilayers for Improving Life Time of Real Tools
JA García, R. Martínez, R.J. Rodríguez, G.G. Fuentes, B. Lerga, M. Rico (Asociación de la Industria Navarra, Spain)
Traditionally the PVD coating marked is covered by the "universal" titanium nitride in a ratio as large as 80%. In the last years, nevertheless, several industrial coaters are focusing their R&D activities towards the development of a new generation of PVD treatments based on: multiplayer and nanolayer architectures, nanocomposites and tribological metal-carbon (Me-C:H) layers. This paper is aimed at reporting on the tribological performance (hardness, friction coefficient, wear resistance, scratch tests) of multilayered coatings such as TiN/CrN, TiN/TiCN and TiN/TiAlN and its comparison to more traditional coatings such as TiN or TiCN. The results of the laboratory tribological analysis are correlated with the test performed under real operating conditions, for instance by evaluating the life time of some coated tools in concrete applications. Among these tools we have investigated: WC inserts and HSS reamers for machining INCONEL and Composites for aeronau-tical applications, WC inserts for special stainless steels machining and cutting blades for polymers. The tribological analysis indicated that the multilayered coatings do not exhibit signifi-cant changes in hardness or friction coefficient with respect to these observed for TiN or TiCN. Contrary, wear resistance and adhesion of the multilayered coatings in-creased significantly with respect to these for TiN or TiCN. The industrial test re-vealed that in some cases these improvements led to time-life by up to 400% with respect to these characteristic for TiN coatings operating under the same wearing conditions.
Time Period WeM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2004 Schedule