Comparative analysis of the implantation-induced structural modifications in GaAs and Ge

Raman spectroscopy was used to analyze disorder evolution, crystalline to amorphous phase transformations as well as modifications of amorphous phase beyond the amorphous threshold in representative compound and elemental tetrahedral semiconductors when implanted in a very wide range of ion fluences (1 x 1012-3 x 1016/cm-1). The particular goal of this study was to separate the effects of the microstructural modifications due to the implantation-induced damage from the effects arising from the incorporation of foreign species into the lattice, which was expected to be important when dealing with very high doses. We have studied monocrystalline GaAs-implanted with Si ions, GaAs samples implanted with equal doses of Ga and As ions to preserve stoichiometry, and Ge samples implanted with Ge ions in the same range of doses. It was found that the evolution of morphology with implantation is very similar in every aspect for both types of GaAs samples, either Si-implanted or Ga + As-implanted. This implies that energy deposition by energetic ions strongly predominates in the process of damage accumulation, making it much more important than the possible influence of chemical effects