A COMBINATION OF ATOMIC FORCE MICROSCOPY AND SECONDARY ION MASS-SPECTROMETRY FOR INVESTIGATION OF ALXGA1-XAS/GAAS SUPERLATTICES

Atomic Force Microscopy (AFM) has been used to characterize the topography of crater bottoms obtained during Secondary Ion Mass Spectrometry (SIMS) investigations of an Al0.35Ga0.65As/GaAs multilayer system. A linear relation between the roughness of the bottoms, which leads to a drop in the dynamic range of the SIMS-signal and in the depth resolution, and the sputter depth of SIMS has been found. The topography found by AFM also supports a mechanism for the ripple formation proposed recently by W. H. Gries. AFM imaging of cleaved cross sections through this multilayer system allowed to determine evenness and thickness of individual layers, which opens up the possibility to improve the depth scale for sputter techniques like SIMS.