Nucleation and growth of crystallites in amorphous antimony layers on as-deposited ultrathin sublayers of metal: Copper, silver, gold, tin and lead

Abstract

Optical microscopy is used for the in situ observation of the nucleation and growth of crystallites in the amorphous antimony layer prepared on an as-deposited ultrathin sublayer of copper, silver, gold, tin or lead. A whole specimen is deposited on a cover glass in a vacuum of 1 × 10 −4 Pa. With the use of sublayers of copper, gold and silver it is possible to measure the growth rate v of antimony crystallites as a function of thickness d Sb of the antimony layer. An analysis of the relation of v to d Sb on the basis of the model previously presented gives such parameters as the thicknesses d s0 and d v0 of surface regions near the substrate and the vacuum respectively and the growth rates u s and u v at surfaces adjacent to the substrate and the vacuum respectively: d s0 = 2.0 nm, d v0 = 5.5nm, u s = 11 μm s −1 and u v = 0.21 μm s −1 when d Cu is 4.3 × 10 −2 nm while d s0 = 0.7 nm, d v0 = 4.4 nm, u s = 7.7 μm s −1 and u v = 0.13 μm s −1 when d Au is 4.0 × 10 −2 nm. The effective activation energy for the growth of crystallites is determined from an Arrhenius plot of v from 30 to 60°C to be, for example, 1.2 eV at d Sb = 3.0 nm and 0.7 eV at d Sb = 5.2 nm when d Cu is 4.3 × 10 −2 nm while it is 1.0 eV at d Sb = 2.2 nm and 0.9 eV at d Sb = 3.7 nm when d Au is 4.0 × 10 −2nm. Sublayers of tin and lead play an extremely progressive role on nucleation of antimony crystallites, resulting in such a high nucleation density that v could not be measured. This originates mainly from the larger area of interface between coupled layers of Sb/Sn or Sb/Pb according to electron microscopy.