MORPHOLOGY OF SI1-XGEX THIN CRYSTALLINE FILMS OBTAINED BY PULSED-EXCIMER-LASER ANNEALING OF HEAVILY GE-IMPLANTED SI

Thin crystalline Si1-xGex films have been obtained by irradiating heav ily (similar to 1.5 X 10(17) ions/cm(2)) Ge-implanted (100) Si with a pulsed ArF excimer laser. The crystallization of the layer amorphized by implantation occurs by a melting-solidification process during and after the laser pulse. The influences of implantation conditions of la ser energy density or number of laser pulses on the layer configuratio n (crystallinity and grain size) are observed by transmission electron microscopy on cross-sections and by grazing X-ray diffraction. The be am energy for implantations ranged from 50 to 150 keV and the laser en ergy density from 0.9 to 1.2 J cm(2). Structures obtained after comple te as well as incomplete melting of the whole amorphized layer have be en investigated. For example: a monocrystalline layer can be observed (implantation: 100 keV; laser: 0.9 J/cm(2), 20 pulses) or successive p olycrystalline layers: large grains of Si1-xGex near the surface on po ly-Si (implantation: 80 keV up to 8 X 10(16) atoms/cm(2) then 50 keV u p to 10(17) atoms/cm(2); laser: 1.2 J/cm(2), 10 pulses). The observati ons also show the grain growth induced by increasing number of pulses.