PART II. Nanostructures of Semiconductor Systems

Note that by inelastic peak shape analysis the in-depth distribution of atoms is determined. This is sometimes not sufficient to establish the complete structure when metal silicides are formed. For example, a pure island structure might as well be interpreted as a distribution corresponding to a metal/silicon alloy layer plus possibly islands of pure metal (a structure similar to SK), because the in-depth distributions of atoms are identical for these structures (see Section 4.2, Fig. 29). These two possibilities may be distinguished by observing chemical shifts of the metal peaks. 

We ran a number of experiments with Ge deposited on Si(OOl) wafers and studied the morphology with inelastic peak shape analysis of X-ray excited electron spectra. Additional measurements by Rutherford backscattering (RBS) and atomic force microscopy (AFM, see Part IV) were performed to give complementary information on the nanostructure of this system. For details of the experiment and the data analysis the reader is referred to the original publications [ 127,128]. 

We prepared five different samples with increasing amounts of germanium. The nominal amount that was deposited was equivalent to 4, 8,12,15, and 35 ML (sample no. 1 -5) of germanium, respectively. Analyzing our data we found that for 

Since SK-growth has previously been reported for this system [130, 131], we tried also a model structure that consisted of a thin layer with a single island type on top. The best fits we obtained for this Stranski-Krastanov structure from sample 

In conclusion, the deposition of Ge on Si(OOl) leads to the formation of a variety of islands, ranging from small, regular islands, covering roughly half the surface area of the substrate, to the well-known hut clusters of medium size and, finally, to extremely high single islands. No wetting layer is observed for this sys- 

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