Study of Radiation-Induced Defects in p-Type Si1−xGex Diodes before and after Annealing |
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Authors: | Tomas Ceponis Stanislau Lastovskii Leonid Makarenko Jevgenij Pavlov Kornelijus Pukas Eugenijus Gaubas |
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Affiliation: | 1.Institute of Photonics and Nanotechnology, Vilnius University, Sauletekio ave. 3, LT-10257 Vilnius, Lithuania; (J.P.); (K.P.); (E.G.);2.Laboratory of Radiation Effects, Scientific-Practical Materials Research Centre of NAS of Belarus, P. Brovki Str.17, 220072 Minsk, Belarus;3.Department of Applied Mathematics and Computer Science, Belarusian State University, Independence Ave. 4, 220030 Minsk, Belarus; |
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Abstract: | In this work, electrically active defects of pristine and 5.5 MeV electron irradiated p-type silicon–germanium (Si1−xGex)-based diodes were examined by combining regular capacitance deep-level transient spectroscopy (C-DLTS) and Laplace DLTS (L-DLTS) techniques. The p-type SiGe alloys with slightly different Ge contents were examined. It was deduced from C-DLTS and L-DLTS spectra that the carbon/oxygen-associated complexes prevailed in the pristine Si0.949Ge0.051 alloys. Irradiation with 5.5 MeV electrons led to a considerable change in the DLT spectrum containing up to seven spectral peaks due to the introduction of radiation defects. These defects were identified using activation energy values reported in the literature. The double interstitial and oxygen complexes and the vacancy, di-vacancy and tri-vacancy ascribed traps were revealed in the irradiated samples. The interstitial carbon and the metastable as well as stable forms of carbon–oxygen (CiOi* and CiOi) complexes were also identified for the electron-irradiated SiGe alloys. It was found that the unstable form of the carbon–oxygen complex became a stable complex in the irradiated and the subsequently annealed (at 125 °C) SiGe samples. The activation energy shifts in the radiation-induced deep traps to lower values were defined when increasing Ge content in the SiGe alloy. |
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Keywords: | silicon– germanium alloy electron beam irradiation-induced defects DLTS |
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