MAGNETRON SPUTTER-DEPOSITION WITH HIGH-LEVELS OF METAL IONIZATION

A new deposition technique has been developed which combines conventio nal magnetron sputter deposition with a rf inductively coupled plasma (RFI). The RFI plasma is located in the region between the magnetron c athode and the sample position, and is set up by a metal coil immersed in the plasma. A large fraction of the metal atoms sputtered from the magnetron cathode are ionized in the RFI plasma. By placing a negativ e bias on the sample, metal ions are then accelerated across the sampl e sheath and deposited at normal incidence. Results from a gridded ene rgy analyzer configured with a microbalance collector and located at t he sample position indicate the level of ionization is low at a few mT orr and rises to > 80% at pressures in the 25-35 mTorr range. Optical measurements of metal ion and neutral emission lines show scaling of t he relative ionization to higher discharge powers. Significant cooling of the plasma electron temperature is observed when high concentratio ns of metal atoms were sputtered into the plasma.