High Current Metal-Ion Source for Activated Deposition

Abstract

A metal ion source with ion currents up to above 5A has been designed and succesfuly applied for activated deposition. It is based on cathodic vacuum are discharges as it is used for deposition of thin films. Such are generate fully ionized plasma with ions, accelerated to kinetic, energies of some ten eV, the ions striking the substrate with these high energies are able in forme amorphous or nanocrystalline films as e.g. hard amorphous carbon films, hard films of metallic nitrides further, the high energies of the particles prevent island growth so that nonporous and smooth layers will be deposited. However, the main disadvantage of vacuum are vaporization - the particle emission - up to now significantly limited the area of application of this deposition technology. Using magnetic fillers - transport of vacuum are plasmas through curved magnetic field - the particles can be removed completely, but the deposition rate is lowered due to significant losses of plasma (about 75%) in the filter to achieve deposition rates of industrial relevance, a new source of pure metal ions, consisting of a high current pulsed are evaporator combined with a sectioned filter unit was developed and successfully tested. The transport efficiency of 25% is of the same order as with best dc-filters, but due to the high current deposition rate of some ten nm per second can be achieved. The deposited layers are tree from particles, holes and pits. As an example films of about 50 nm have been deposited in some seconds homogeneously (thickness variation below 5%) on a 4 inch substrate. Repetition rates can be adjusted from more than 100 Hz down to single pulses in dependence on the allowed thermal input. The following applications were already processed successfully. 1. Metal ion source for plasme immersed implantation (PIII) an effective way for 3 dimensional implantation of industrial parts 2. Hard, amorphous carbon films with a hardness up to above 70 GPa for hard disk and compact disc depositions as well as protective layer for optics and tools 3. Deposition of dropletfree TiN depositions for advanced applications 4. Transparent layers of Al 2 O 3 with medium hardness for protection of optical elements made from organic glasses 5. Metallic films, as copper for the metallization of microelectronic structures and for high reflecting surfaces.