2.1.    99-02-17990
2.2.    Trushin Yuri Vladimirovich
2.3.    Investigation of physical processes under impact of
        heavy ions and clusters on surface region of semiconductor
        heterostructures
2.4.    2001
2.5.    2
2.6.    Diring the year 2000 the second part declared in the
        investigation program was achieved by the scientific
        group. It includes studies of characteristics and features
        of  a dense cascade evolution under bombardment of heavy ions
        and clusters, as well as its effect on the secondary emission
        (sputtering) and dynamic modification of surface of materials of
        diferent kinds including the semiconducter heterostructures.
        In the experimental part we studyed the influence of growth and
        annealing temperatures on the formation of ultra-thin delta markers
        in order to develop  the technology of formation of test structures
        with equididstant delta-layers of Sb in the GaAs matrix. As a result,
        we achieve the technilogy of low-temperature molecular-beam epitaxy,
        which allows one to create test structures that contain Sb markers
        with thicknesses of about 1.5 mololayer and with the spreading
        which not exceeds the value of  10..15 Angstroms. In addition,
        the tryals of the universal charge clusters test source in the
        mode of generation of the negative charged Si clusters  (up to
        3-atomic clusters) were carried out.
         Theoretical part of the present work is concerned with studies
        of the cascade sputtering in the dense (non-linear)  mode by
        numerical simulation using the Monte-Carlo and Molecular dynamics
        methods. In the frame  of this stage of investigation we have
        elicited and formulated the physical criterions for estimation of
        the significancy of  non-linear (dense) effects  in a cascade for
        selected conditions of irradiation.
        The investigations of the features of the etching of semiconducter
        heterostructers by Cs heavy ions and oxygen molecular ions were
        performed as well. The comparision with related SIMS experiments
        on the specimens characterized by TEM method allow us to elaborate
        the recently obtained values of the displacement thershold energies
        of Al and In impurity atoms in the GaAs matrix.

        The investigations of defect evolution in silicon carbide
        under high-dose Al and N ion irradiation has been carried our
        taking into account  internal  stress  fields due to different
        radiation defects.  Defect evolution in oxygen subsystem of
        PLZT ferrolelectric ceramics under neutron irradiation and
        subsequent annealing has been investigated.
        The studyies of the influence of these defects on  polarization
        of the material  have been carried out.
        In addition, on the present stage we developed the numerical
        simulation  method for studying of sputtering under ion and cluster
        bombardment at the projectiles energies of about (0.1-1) keV/atom.
2.7.    A.F.Ioffe Physico-Technical Institute of the Russian
        Academy of Sciences