Ion Assisted Evaporation System for Complex Thin Films Deposition

  Alex Axelevitch  ,  Boris Apter  
Engineering Faculty, Holon Institute of Technology (HIT)

Ion assisted deposition represents simultaneous or periodic bombardment of the substrate by atomic-sized energetic neutral and ionized particles. This process results in growth of thin films with the properties differ from the films obtained by usual thermal evaporation method. This method called also as ion plating or ion vapor deposition is used for improving such properties of thin films as adhesion, wear resistance, density of metal films etc. A specific interest is in the doping of growing thin semiconductor films. For this goal, the ion assisted deposition system was designed and investigated in our work.

The novel deposition setup is based on the modified multipurpose laboratory vacuum station equipped with a two-stage vacuum system enabling the base pressure of about 3×10-5 Torr. The configuration of the novel ion plating system is similar to the conventional vacuum thermal evaporation arrangement supplemented with the high-voltage feedthroughs. An annular positive electrode built from tungsten is situated between an evaporation source and a substrate. The negative electrode surrounds the substrate to direct the ion flux to it. Before deposition of thin films, the reactive gas is introduced in the vacuum chamber pumped up to the base pressure. The glow discharge in this gas influences on the growing film and changes their properties. The novel deposition system enables to dope the growing films. The deposition process was studied using in-situ emission spectroscopy method. As shown, the glow discharge parameters significantly change properties of deposited thin films.