Laser thermal annealing effects on single crystal gallium phosphide

We have studied the laser thermal annealing LTA effects on single crystal GaP. The samples have been analyzed by means of Raman spectroscopy, glancing incidence x-ray diffraction GIRXD , and transmission electron microscopy TEM measurements. After LTA process, the Raman spectra of samples annealed with the highest energy density show a forbidden TO vibrational mode of GaP. This result suggests the formation of crystalline domains with a different orientation in the annealed region regarding the GaP unannealed wafer. This behavior has been corroborated by GIXRD measurements. TEM images show that the LTA produces a defective layer with disoriented crystalline domains in the surface. The depth of this defective layer increases with the energy density of LTA. The lack of crystallinity after LTA processes could be related with the high bond energy value of GaP. © 2009 American Institute of Physics. doi:10.1063/1.3187902