Citation

Karmalkar S, Kumar VP. Journal of the Electrochemical Society 2004; 151(9): C554-C558.

Copyright

(Copyright © 2004)

DOI

10.1149/1.1773582

PMID

unavailable

Abstract

We present a study of the adhesion and current-voltage characteristics of as-plated electroless nickel deposits on polished crystalline silicon activated using nickel and palladium. A highlight of this study is the derivation of practically significant trends by collating the results of a large number of simple experiments as a function of substrate doping polarity, doping level, plating area, and plating duration. The study reveals that palladium activation is most effective on P+ substrates while nickel activation is most effective on N+ substrates, due to the requirement of substrate holes in the former activation and electrons in the latter. An activation process always improves adhesion, but, in some cases, degrades the electrical properties of the plating-silicon interface, because it introduces an intermediate suicide layer between nickel and silicon. Electroless nickel layer adheres better to nickel activated silicon, than to palladium activated silicon. However, the rectifying nature of the electroless nickel contacts on palladium activated silicon is superior to those on nickel activated silicon. Further, palladium suicide forms at 200°C, which is much lower than the temperature of 400°C required for nickel suicide formation. © 2004 The Electrochemical Society. All rights reserved.

Language: en

Keywords

Silicon; Scanning electron microscopy; Electric currents; Nickel; Doping (additives); Electric potential; Energy dispersive spectroscopy; Arsenic; Palladium; Crystalline materials; Adhesion; Silicide layers; Chemical activation; Current-voltage characteristics; Electroless plating; Integrated circuits; Microelectromechanical devices; Microelectromechanical systems (MEMS); Palladium activation