Mechanical & Materials Engineering, Department of
Date of this Version
6-3-2003
Citation
United States Patent No.: US 6,572,933 B1 Jun. 3, 2003
Abstract
Process for forming abherent coatings using plasma processing. Plasma Immersion Ion Processing (PIIP) is a process where energetic (hundreds of eV to many tens of keV) metallic and metalloid ions derived from high-vapor-pressure organometallic compounds in a plasma environment are employed to desposit coatings on suitable substrates, which coatings are subsequently relieved of stress using inert ion bombardment, also in a plasma environment, producing thereby strongly adherent coatings having chosen composition, thickness and density. Four processes are utilized: sputter-cleaning, ion implantation, material deposition, and coating stress relief. Targets are placed directly in a plasma and pulse biased to generate a non-line-of-sight deposition without the need for complex fixturing. If the bias is a relatively high negative potential (20 kV-100 kV) ion implantation will result. At lower voltages (50 V-10 kV), deposition occurs, and the extent of the surface modification can routinely be extended between 1 um and 10 um. By combining plasma based implantation and film deposition, coatings with greatly reduced stress are possible, allowing the ultimate coating thickness to be expanded to tens of microns.
Comments
US govt doc. Public domain