CHARACTERIZATION OF THIN ELECTROLESS NICKEL COATINGS

The early stages of electroless nickel growth on copper {100} were cha racterized using scanning tunneling and transmission electron microsco py. A long induction time was observed prior to nickel deposition. Sca nning tunneling microscopy analysis showed all deposits grew by the la teral spreading of atomic layers followed by the formation and coalesc ence of three-dimensional structures. Transmission electron microscopy studies showed low-phosphorus electroless nickel coatings consisted o f discrete islands which coalesced into continuous films. Low-phosphor us deposits were crystalline. Medium-phosphorus deposits were more con tinuous than low phosphorus coatings and exhibited a semiamorphous str ucture. High-phosphorus deposits were continuous and amorphous. This s ize of coherently diffracting crystallites decreased with an increase in the phosphorus content of the nickel films. Three dimensional surfa ce structures observed with STM agrees with the size of the crystallit es from TEM analysis.