SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 51: Nitrides: Preparation and Characterization

HL 51.1: Talk

Friday, March 31, 2023, 09:30–09:45, POT 112

High resistive buffer layers by Fermi-level engineering — •Armin Dadgar, Ralf Borgmann, and André Strittmatter — Otto-von-Guericke-Universität Magdeburg, FNW-IfP, Universitätsplatz 2, 39106 Magdeburg

We present a novel method to increase the resistivity of semiconductor buffer layers by aligning the Fermi level using a donor and an acceptor dopant of which one preferentially is a deep level placed in the lower (acceptor) or upper (donor) half of the energy band-gap. Potential doping sequences in GaN were simulated by nextnano software showing that the average Fermi-level position of alternately donor and acceptor doped layers can be shifted to the midgap position. This shift decreases the free carrier concentration and increases the resistivity as demonstrated for GaN:C / GaN:Si layer stacks. In structures grown by metalorganic vapor phase epitaxy, less charging and hysteresis effects are observed upon polarity changing between electrical contacts placed at surface and substrate. Also, the reduced total deep level concentration improves resistivity under electron and hole injection and the overall breakdown voltage by more than 20 %.