Aligned island formation using step-band networks on Si(111)

We have achieved control of island formation using a patterned Si(111) surf ace with a periodic array of atomic-step bands and holes. Liquid metals, Au -Si or Ga, migrate on the patterned surface by annealing and form an island at a particular position in each pattern unit. The islands show highly uni form positions and narrow size distributions. To obtain such good uniformit y, the diffusion length of surface atoms should be comparable with the patt ern period. High mobility on step bands is also a necessary factor. Periodi c arrays of Au islands are used as seeds for selective growth using a vapor -liquid-solid reaction. (C) 1999 American Institute of Physics. [S0021-8979 (99)04218-8].