Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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Nanoscale n++-p junction formation in GeOI probed by tip-enhanced Raman spectroscopy and conductive atomic force microscopy
Prucnal, S.; Berencen, Y.; Wang, M.; Georgiev, Y.; Erbe, A.; Khan, M. B.; Böttger, R.; Hübner, R.; Schönherr, T.; Kalbacova, J.; Vines, L.; Facsko, S.ORC; Engler, M.; Zahn, D. R. T.; Knoch, J.; Helm, M.; Skorupa, W.; Zhou, S.ORC
Ge-on-Si and Ge-on-insulator (GeOI) are the most promising materials for the next-generation nanoelectronics that can be fully integrated with silicon technology. To this day, the fabrication of Ge-based transistors with a n-type channel doping above 5 × 1019 cm−3 remains challenging. Here, we report on n-type doping of Ge beyond the equilibrium solubility limit (ne ≈ 6 × 1020 cm−3) together with a nanoscale technique to inspect the dopant distribution in n++-p junctions in GeOI. The n++ layer in Ge is realized by P+ ion implantation followed by millisecond-flashlamp annealing. The electron concentration is found to be three times higher than the equilibrium solid solubility limit of P in Ge determined at 800 °C. The millisecond-flashlamp annealing process is used for the electrical activation of the implanted P dopant and to fully suppress its diffusion. The study of the P activation and distribution in implanted GeOI relies on the combination of Raman spectroscopy, conductive atomic force microscopy, and secondary ion mass spectrometry. The linear dependence between the Fano asymmetry parameter q and the active carrier concentration makes Raman spectroscopy a powerful tool to study the electrical properties of semiconductors.
We also demonstrate the high electrical activation efficiency together with the formation of ohmic contacts through Ni germanidation via a single-step flashlamp annealing process.
Keywords: GeOI, ion implantation, flash lamp annealing, doping, TERS

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  • Secondary publication expected from 28.06.2020

Publ.-Id: 29401 - Permalink