Lang W.,CAS Shenyang Institute of Metal Research |
Xiao J.,CAS Shenyang Institute of Metal Research |
Xiao J.,Hunan YKH Surface Engineering Co. |
Gong J.,CAS Shenyang Institute of Metal Research |
And 3 more authors.
Jinshu Xuebao/ Acta Metallurgica Sinica | Year: 2010
Arc ion plating (AIP) has been widely utilized in the deposition of various kinds of thin solid films due to the excellent characteristics of the arc plasma produced from an active cathode spot that emits ions of cathode material, as well as electrons. In AIP process, the cathode spot is usually steered by an external magnetic field. Cathode spot motion is the key factor because it affects the physical characteristics of the vacuum arc plasma, the utilization of the cathode material, the emission of macroparticles (MPs) and the quality of subsequent films containing these MPs. Therefore, cathode spot dynamics should be understood practically under a compound external magnetic field, such as in axisymmetric magnetic field (AMF), for industrial applications. An AMF produced by using an adjustable electromagnetic coil associated with a concentric magnetic flux guider was applied to the cathode surface to investigate the influence of the AMF on the arc cathode spot motion. The distribution of the magnetic field was simulated by the finite element method (FEM) software. The magnetic field intensity was measured by an SHT-V magnetometer and the distributions of magnetic field with different intensities were analyzed. Based on the results of FEM simulation and the physical mechanism of the arc cathode spot discharge, the effects of magnetic-field components and AMF on the cathode spot movement were discussed. The results showed that increasing the AMF intensity can strongly influence cathode spot movement. In the case of a weak AMF, the cathode spot moves randomly on the cathode surface. With increasing AMF, there is an increasing tendency for the cathode spot to rotate and drift toward the cathode target edge. The increase in the transverse magnetic field (TMF) intensity, BT, can accelerate the rotational velocity of the cathode spot, increase the arc voltage and decrease the arc current. With a relatively strong AMF (BT ≈30 Gs), the cathode spot rotates near the edge of the cathode surface and is confined to a circular trajectory. A new arc cathode spot is ignited, splits, and is extinguished repeatedly on the cathode surface, which can be observed at intervals of about 0.5 s, while there is an obvious erosion track left at the bottom of the cathode edge. ©.
Lang W.C.,CAS Shenyang Institute of Metal Research |
Lang W.C.,Hunan YKH Surface Engineering Co. |
Xiao J.Q.,CAS Shenyang Institute of Metal Research |
Xiao J.Q.,Hunan YKH Surface Engineering Co. |
And 4 more authors.
Vacuum | Year: 2010
Cathode spot motion and macroparticles (MPs) reduction on related films are the two main issues in the application of the vacuum arc deposition (VAD). In the present work, an axisymmetric magnetic field (AMF) was applied to the cathode surface to investigate the influence of the AMF on the cathode spot motion and the MPs reduction on TiN films. The results show that the AMF affected the cathode spot motion by redistributing the dense plasma connected with the initiation of the new spot. With increasing AMF, there is an increasing tendency for the cathode spot to rotate and drift toward the cathode target edge. Based on the results of FEM simulation and the physical mechanism of the cathode spot discharge, the mechanism of the cathode spot motion in the AMF was discussed. The morphology, detailed size distribution, and roughness of the resultant TiN films were systematically investigated. Fewer and smaller MPs ejection is observed with an increase in the transverse component of AMF. The effect of the AMF on the MPs reduction on TiN films was discussed, and the results were compared with the theoretical predictions. © 2010 Elsevier Ltd. All rights reserved.