Synchrotron studies of implanted In xGa 1− xAs

Abstract

MOCVD grown epitaxial layers of In 0.53Ga 0.47As/InP were implanted with 1.5 MeV Se ions or 1.0 MeV Si ions at room temperature and at liquid nitrogen temperature. A wide range of ion doses exceeding 10 15 ions/cm 2 was applied. White beam synchrotron section and projection topography as well as rocking curve measurements were used for the characterisation of samples. The aim of the experiment was the evaluation of the dose dependence of ion implantation induced strain and the determination of amorphisation threshold. It was found that the implantation performed at room temperature did not cause lattice amorphisation even for highest applied doses, i.e. 2×10 15 Se/cm 2. The strain induced by 1.5 MeV Se ions implantation at room temperature increases with the ion dose and reaches its maximum for 3×10 14 ions/cm 2. Further increase of the dose resulted in the decrease of the strain. Ion implantation performed at liquid nitrogen temperature led to amorphisation of the sample at doses of the order of 10 13 ions/cm 2. The amorphisation manifested itself in the significant decrease of the implanted layer maximum in the rocking curve. A strain modulation fringes characteristic for non-monotonic strain profiles were observed in some Bragg-case section topographs.