Self-assembled growth of nanostructural Ge islands on bromine-passivated Si(111) surfaces at room temperature

We have deposited relatively thick (∼60 nm) Ge layers on Br-passivated Si(111) substrates by thermal evaporation under high vacuum conditions at room temperature. Ge has grown in a layer-plus-island mode although it is different from the Stranski-Krastanov growth mode observed in epitaxial growth. Both the islands and the layer are nanocrystalline. This appears to be a consequence of reduction of surface free energy of the Si(111) substrate by Br-passivation. The size distribution of the Ge nanoislands has been determined. The Br-Si(111) substrates were prepared by a liquid treatment, which may not produce exactly reproducible surfaces. Nevertheless, some basic features of the nanostructural island growth are reasonably reproducible, while there are variations in the details of the island size distribution.     

The statistics of dielectric breakdown in MOS capacitors under static and dynamic voltage stress

The statistics of dielectric breakdown at fields 8 MV/cm has been studied under both static (constant voltage) and dynamic (ramped voltage) conditions. MOS capacitors of the same size and from the same wafer were used for all measurements. Data from both types of test conformed to a Weibull distribution. The Weibull parameters a and b, which determine the time and field dependence of breakdown, were calculated from static tests at various applied fields and independently from dynamic tests at various ramp-rates. The values of a and b were: a 0.24; b 6.89 and a 0.34; b 6.55, from static and dynamic tests respectively. The similarity of the values for the two pairs of Weibull parameters suggests that breakdown proceeds by the same mechanism in both types of test.     

The infrared and Raman spectra of solid CsSbF 5OH and CsSbF 4(OH)2

The infrared and Raman spectra of solid CsSbF ₅OH and CsSbF ₄(OH)₂ have been studied to determine the effect of replacing one or more F^--ions by OH^--ions in the SbF^-₆-ion. The results have been obtained in the frequency ranges where the Sb-F and Sb-OH stretching modes are known to occur. The spectra are in agreement with a low site symmetry for the SbF ₅OH^--ion in CsSbF ₅OH but are largely inconclusive as to whether the OH-groups in CsSbF ₄(OH)₂ have cis- or trans-symmetry.