GAAS MICROCRYSTAL GROWTH ON SEMICONDUCTOR SURFACES BY LOW-ENERGY FOCUSED ION-BEAM

A position controlled or density controlled GaAs microcrystal growth f rom Ga droplets was attempted using a low energy focused ion beam syst em. Ga ions from a liquid Ga ion source were accelerated up to 10 kV t o produce a focused ion beam. Subsequently the ions were given a posit ive bias to reduce their kinetic energy by a four-element retarding le ns system. The Ga ions with a 30 eV kinetic energy softly landed on a S-terminated GaAs surface and formed a series of Ga droplets or Ga dro plets matrix. After initiating the As molecule supply, GaAs microcryst als were found to grow from these Ga droplets. The low energy focused ion beam was also applied to create nucleation sites of Ga droplets on an As-terminated Si (001) surface at 100 eV. Ga droplets with high de nsity were formed on a region where As atoms were removed partially on the Si surface. From these results, the low energy focused ion beam w as found useful for position control or density control of GaAs microc rystals on semiconductor materials. (C) 1998 American Vacuum Society.