Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 63: II-VI-Compounds

HL 63.6: Talk

Wednesday, March 16, 2011, 17:15–17:30, POT 151

Ion-beam-induced damage formation in CdTe at 15K — Carl Willem Rischau, •Claudia Sarah Schnohr, Elke Wendler, and Werner Wesch — Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena, Germany

Ion implantation studies on CdTe are of interest regarding a possible application of this technique in the fabrication of CdTe devices, but also with respect to the fundamental understanding of ion-beam-induced damage formation in II-VI compounds. Studies at room temperature exhibit some interesting features like defects extending much deeper into the crystal than the calculated range of the ions and a high resistance to amorphization even after prolonged irradiation with ion fluences as high as several 10¹⁶ ions/cm².

In order to study a possible thermal origin of these effects, we irradiated CdTe single crystals with 270keV Ar and 730keV Sb ions at 15K and analyzed the damage formation in-situ using Rutherford backscattering spectrometry (RBS) in channeling direction. Defect profiles calculated from the RBS spectra using the computer code DICADA show a flat defect distribution which extends to a depth of up to five times the projected range of the ions despite the very low temperature. The post-range defects in CdTe thus do not seem to be of thermal origin, but are instead believed to result from migration driven by the electronic energy loss. Furthermore, CdTe is not rendered amorphous at 15K even after irradiation with several 10¹⁶ ions/cm², suggesting that the high resistance to amorphization of CdTe is caused by the high ionicity of the material rather than thermal effects.