Ablation plasma ion implantation (APII) for deposition of metal coatings

Abstract

Summary form only given, as follows. We present experimental results on a novel technique for deposition and implantation of metal coatings by means of ions generated by KrF laser ablation of metals. The pulse-biased substrate accelerates ablated ions. APII was initially demonstrated by implanting iron ions into silicon substrates at bias voltages up to negative 10 kV. Materials have been analyzed by Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). Results definitively show that ion implantation has occurred, consistent with a maximum effective ion energy of about 8 keV. The lower effective energy is due to voltage droop and limited penetration of the overlying Fe film. XPS performed during an argon ion etch shows a depth profile confirming Fe implantation and deposition on the Si substrate. APII ion bombardment amorphizes the deposited film. Plasma diagnostics include: dye-laser interferometry, optical emission spectroscopy, Langmuir probe and Faraday cup for species identification as well as electron and ion densities and temperatures. Most recently, research has concentrated on ion implantation and deposition of hard coatings over softer metals, e.g., Ti over Al. Atomic force microscopy (AFM) data show that the APII deposited Ti film is smoother than the baseline laser-deposited film. A substrate bias voltage of -4 kV is adequate for smoothing to occur on Ti films over 6061 alloy Al substrates.