ATOMIC-FORCE MICROSCOPY INVESTIGATION OF ARGON-BOMBARDED INP - EFFECTOF ION DOSE DENSITY

Samples of InP(100) n-doped with S atoms to 4 x 10(18) cm(-3) and to 6 x 10(18) cm(-3) were bombarded with 0.5 and 5 keV argon ions. The ang le of incidence of the 5 keV ions was 71 degrees with respect to the s ample normal and 41 degrees for the 0.5 keV ions, The resulting topogr aphy development was investigated by means of atomic force microscopy (AFM) and transmission electron microscopy (TEM) of Cr-C replicas of t he bombarded surfaces, There was a correlation between the AFM images and those from the TEM replicas. At the same magnification the AFM ima ges showed more detail. The surface roughness in the AFM images was qu antified using the software of the AFM instrument, in the range 5 x 10 (14)-2 x 10(18) Ar+ cm(-2), there was a linear relationship between th e roughness parameter and the logarithm of the ion dose density. This fact excludes a seeding sputter erosional theory for the explanation o f the development of bombardment-induced topography on InP. At the hig her dose densities, ripple formation was observed, The dose density de pendence of average wavelength of the ripples did not correlate with t he predictions of the Bradley-Harper theory.