화학공학소재연구정보센터
Applied Surface Science, Vol.258, No.9, 4144-4147, 2012
Nanostructures on GaAs surfaces due to 60 keV Ar+-ion beam sputtering
The effect of 60 keV Ar+-ion beam sputtering on the surface topography of p-type GaAs(1 0 0) was investigated by varying angle of incidence of the ion (0-60 degrees) with respect to substrate normal and the ion fluence (2 x 10(17)-3 x 10(18) ions/cm(2)) at an ion flux of 3.75 x 10(13) ions/cm(2)-s. For normal incidence and at a fluence of 2 x 10(17) ions/cm(2), holes and islands are observed with the former having an average size and density of 31 nm and 4.9 x 10(9) holes/cm(2), respectively. For 30 degrees and 45 degrees off-normal incidence, in general, a smooth surface appears which is unaffected by increase of fluence. At 60 degrees off-normal incidence dots are observed while for the highest fluence of 3 x 10(18) ions/cm(2) early stage of ripple formation along with dots is observed with amplitude of 4 nm. The applicability and limitations of the existing theories of ion induced pattern formation to account for the observed surface topographies are discussed. (C) 2011 Elsevier B. V. All rights reserved.