CHARACTERIZATION OF THIN ELECTROLESS NICKEL COATINGS

The early stages of electroless nickel growth on copper {100} were characterized using scanning tunneling and transmission electron microscopy. A long induction time was observed prior to nickel deposition. Scanning tunneling microscopy analysis showed all deposits grew by the lateral spreading of atomic layers followed by the formation and coalescence of three-dimensional structures. Transmission electron microscopy studies showed low-phosphorus electroless nickel coatings consisted of discrete islands which coalesced into continuous films. Low-phosphorus deposits were crystalline. Medium-phosphorus deposits were more continuous than low phosphorus coatings and exhibited a semiamorphous structure. High-phosphorus deposits were continuous and amorphous. This size of coherently diffracting crystallites decreased with an increase in the phosphorus content of the nickel films. Three dimensional surface structures observed with STM agrees with the size of the crystallites from TEM analysis.