Study of Extended Defect Structure Induced by Pulsed Laser Annealing in Implanted Silicon Crystals
(a) Institute of Physics, Polish Academy of Sciences, Al. Lotniko´w 32/46,PL-02-668 Warsaw, Poland(b) Institute of Experimental Physics, Warsaw University, Ul. Hoz˙a 69,PL-00-681 Warsaw, Poland(c) Institute of Electron Technology, Al. Lotniko´w 32/46, PL-02-668 Warsaw, Poland(Received October 1, 1998)An analysis of extended defects generated during annealing by pulsed excimer laser radiation in sili-con crystals implanted with Ge ions is presented. The investigation was performed by means of twocomplementary methods: the interference-polarizing microscopy and the Lang X-ray transmissiontopography. The existence of extended defects was revealed. It has been stated that the distributionof these defects depends on the distribution of the power density in the laser beam cross-section.
Composition and structure of Si–Ge layers produced by ion implantation and laser melting
Si samples (001) oriented have been implanted with 10 17 74 Ge/cm 2 (17.7 at. % maximum Ge concentration) and then pulse annealed with either ruby or excimer (XeCl) lasers in the energy density range from 0.1 to 1.5 J/cm 2 . Compositional and structural characterization has been performed showing that for both laser wavelengths the final product of the annealing process is a single crystal characterized by a surface layer about 150 nm thick whose composition is Si 0.9 Ge 0.1 . While after ruby laser irradiations defects are present even in the fully recrystallized samples, after XeCl irradiations good strained layers in epitaxy to the underlying silicon crystals and free from misfit dislocations are produced. Structural characterization of the regrown films indicates that the governing factor for the recovery of the crystalline quality and for the “building up of strain” is the state of the implantation “end-of-range defect” layer. When this defected layer is not melted, textured columnar grains are formed. Upon melting of the end-of-range defect layer, a single crystal epitaxial layer under compressive strain is formed.
Mean field model of a game for power
Abstract Our aim is to model a game for power (equivalent to total energy) as a dynamical process, where an excess of power possessed by a player allows him to gain even more power. Such a positive feedback is often termed as the Matthew effect. Analytical and numerical methods allow to identify a set of stationary states, i.e. fixed points of the model dynamics. The positions of the unstable fixed points give an insight on the basins of attraction of the stable fixed points. The results are interpreted in terms of modeling of coercive power.