OSCILLATORY EVOLUTION OF AN ION-BOMBARDED INSB(100) SURFACE

Low energy ion-scattering and ion-recoil (LEIS and LEIR) spectroscopie s have been used to monitor the structure and composition of an InSb ( 100) surface during continuous irradiation with argon ions (4.8 keV) d irected at grazing incidence. Oscillations in both the scattered and r ecoil ion intensities have been observed during all bombardment sequen ces (for doses > 2 x 10(16) ions/cm2). The periods of these oscillatio ns show some dependence on the experimental geometry, and are close to those predicted for sputter-removal of one or two surface layers. Int erestingly, the surface shows no sign of becoming amorphous even follo wing excess ion bombardment. Details of the variations in surface comp osition are assigned, not only to layer-by-layer depth profiling, but also by rapid diffusion of Sb to the surface from the Sb depleted latt ice. These data indicate that LEIS and LEIR can be used to monitor com position profiles with monolayer depth resolution such that different states of the same surface can be achieved simply and controllably by terminating ion bombardment following a pre-determined irradiation dos e.