CHARACTERIZATION OF MAGNETRON-SPUTTERED PARTIALLY-IONIZED ALUMINUM DEPOSITION

A rotating magnet de planar magnetron with a 33-cm diameter aluminum t arget is coupled with a secondary plasma source to ionize the sputtere d metal neutral flux to control the angular distribution of the flux a rriving at the surface of the substrate. For this purpose, a radio-fre quency (rf) plasma is created between the sputtering target and substr ate by a three-turn coil located in the vacuum chamber. The rf plasma increases the electron temperature and density, which results in signi ficant ionization of the neutral metal flux from the sputtering target . By applying a small negative bias to the substrate, metal ions are d rawn to the substrate at normal incidence. A gridded energy analyzer a nd a quartz crystal microbalance (QCM) were used to determine the ion and neutral deposition rates. From this, the ionization fraction of th e flux incident onto the QCM is determined. (C) 1998 American Vacuum S ociety.