EXAFS study of the amorphous phase of InP after swift heavy ion irradiation

Structural parameters of InP amorphised by electronic energy deposition were determined using extended X-ray absorption fine structure spectrometry. Samples were prepared with 180 MeV Au¹³⁺ irradiation and a combination of semiconductor processing techniques and chemical etching. At the In K-edge of the amorphous material, only the first shell scattering peak is observed demonstrating the structural disorder introduced by the swift heavy ion irradiation. Furthermore, the presence of chemical disorder in the form of In-In bonds is shown. These homopolar bonds amount to 10% of the total number of In coordinations which is 3.73 ± 0.41 and thus less than the crystalline value of 4. In general, these results are similar to those reported for InP and other compound semiconductors amorphised by conventional ion implantation with a dominant nuclear energy deposition. However, slight differences in the values of the structural parameters obtained remain and further studies are necessary to determine their origin.