Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 39: Silicon-based Semiconductors II
HL 39.1: Vortrag
Dienstag, 8. März 2016, 14:45–15:00, H14
Doping of 4H-SiC with group IV elements — •Maximilian Rühl1, Tomasz Sledziewski1, Günter Ellrott1, Theresa Palm1, Heiko Weber1, Michael Krieger1, and Michel Bockstedte2,3 — 1Department of Physics, Applied Physics, FAU Erlangen-Nürnberg, Germany — 2Department of Physics, Solid State Theory, FAU Erlangen-Nürnberg, Germany — 3Department of Chemistry and Physics of Materials, Universität Salzburg, Austria
An enhancement of the electrical conductivity of 4H-SiC was achieved recently by in-situ germanium doping [1]. Since Ge behaves isoelectrically in SiC, a Ge-related modification of the defect equilibrium was suggested. Here we combine experiment and theory to reveal the underlying physics. Our analysis of n-type 4H-SiC samples implanted with Ge or tin (Sn) by deep level transient spectroscopy (DLTS) shows that the mobility-limiting Z1/2 center can be strongly reduced with increasing implantation dose. Simultaneously new defects are formed which are assumed to be Ge-/Sn-related. Using hybrid density functional theory we investigate the electronic properties and abundance of Ge-related defects. We find that the most abundant ones are the electrically inactive substitutional center at the Si-site (GeSi), the deep substitutional center at the C-site (GeC), and a complex with a carbon vacancy (GeSi-VC). The GeSi-VC complex can be associated with new defect centers observed in DLTS. Our combined approach suggests that kinetic effects drive the observed reduction of Z1/2 (=VC , [2]).
[1] Sledziewski et al. Mater. Sci. Forum 778-780 (2014) 216.
[2] Kawahara et al. J. Appl. Phys. 115 (2014) 143705.