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.
Laser induced phase transitions in Si and Ge implanted Si substrates
Computer calculations based on the Fourier equation of the heat flow are reported for ruby and excimer laser irradiation of silicon substrates implanted with Ge and Si ions. The calculated thresholds for the epitaxial crystallization are compared to the experimental values determined by Rutherford backscattering spectrometry (R BS) and channeling measurements. Good agreement is achieved between calculated and experimental values for ruby laser irradiation of Si and Ge implanted samples, while for the excimer laser irradiation of Ge implanted samples the numerical simulations do not agree with the experimental values. A reduced reflectivity of the surface during the melting of the Ge implanted samples must be considered in order to reproduce the experimental data. The study indicates that a complicated melting dynamics occurs during laser irradiation with the excimer laser with an inhomogeneous melting caused by the Gaussian Ge concentration profile.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.