E.I. Girargizov et al/Ultramicroscopy 82(2000)57-61 282828KV 19mD16 Fig1. An oriented array of silicon whiskers grown on a(11 1) whiskers oriented array of silicon tips prepared from silicon Fig. 3. Si substrate by the vapor-liquid-solid mechanism. 285929KX8,9801nD Fig. 2. An intermediate stage of transformation of a silicon hiker into a silicon tip. substrate with the gold particles is installed into a crystallization chamber. Purified hydrogen with Sicl4 vapors is passed through the chamber. The ubstrate is heated up to about 800-900C. The gold particles are melted when they come in contact with the silicon substrate. Silicon-gold alloy drop lets are formed according to the silicon-gold phase diagram. At the temperatures indicated, the chemical Fig 4. A high-resolution transmission-electron-microscope im- reaction SiCl4 +H2+Si+ 4HCl proceeds prefer- age of the sharpened silicon tip entially at the surface of the droplets. Silicon atoms that are evolved by the reaction supersaturate the pushed out of the substrate, and silicon columns droplets, and the excess silicon is deposited at the ("whiskers")are formed under the droplets, the droplet-silicon substrate interface. The droplets are diameter of the whiskers being determined by theFig. 1. An oriented array of silicon whiskers grown on a (1 1 1)- Si substrate by the vapor}liquid}solid mechanism. Fig. 2. An intermediate stage of transformation of a silicon whisker into a silicon tip. Fig. 3. An oriented array of silicon tips prepared from silicon whiskers. Fig. 4. A high-resolution transmission-electron-microscope im￾age of the sharpened silicon tip. substrate with the gold particles is installed into a crystallization chamber. Puri"ed hydrogen with SiCl4 vapors is passed through the chamber. The substrate is heated up to about 800}9003C. The gold particles are melted when they come in contact with the silicon substrate. Silicon}gold alloy drop￾lets are formed according to the silicon-gold phase diagram. At the temperatures indicated, the chemical reaction SiCl4 #H2 PSi#4HCl proceeds prefer￾entially at the surface of the droplets. Silicon atoms that are evolved by the reaction supersaturate the droplets, and the excess silicon is deposited at the droplet}silicon substrate interface. The droplets are pushed out of the substrate, and silicon columns (`whiskersa) are formed under the droplets, the diameter of the whiskers being determined by the 58 E.I. Givargizov et al. / Ultramicroscopy 82 (2000) 57}61