Electrostatic theory of metal whiskers

Abstract

Needle shaped whiskers grow on various metal surfaces often across leads of a package causing current leakage or short circuits and raising reliability issues in electronic components. The nature of metal whiskers remains a mystery after several decades of research. Here, the existence of metal whiskers is attributed to the energy gain due to electrostatic polarization of needle shaped metal filaments in the electric field. The field is induced by surface imperfections: contaminations, oxide states, grain boundaries, etc. A proposed theory provides closed form expressions and quantitative estimates for the whisker nucleation and growth rates, explains the range of whisker parameters and effects of external biasing, and predicts statistical distribution of their lengths.