Whisker taper induced by heterogeneous chemical reaction.

Experimental data are presented on the taper of silicon whiskers grown in an open chloride system. The whisker taper is shown to depend on the crystal growth rate, whisker radius and length, and process parameters. The experimental data are analyzed under the assumption that the size of the liquid droplet on the whisker tip decreases because of the heterogeneous chemical reaction responsible for the etching of the metallic component of the alloy. The influence of the crystal radius and vapor phase composition on the flux that leads to a decrease in the size of the liquid droplet. A model is proposed for whisker tapering as a result of the heterogeneous chemical reaction responsible for the etching of the metal on the surface of the liquid phase, and conditions for the growth of zero-taper whiskers are discussed. [ABSTRACT FROM AUTHOR]