SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 16: Quantum dots: Transport (joint session HL/TT)
HL 16.5: Talk
Tuesday, March 28, 2023, 10:30–10:45, POT 151
Highly Conductive Silicon Nanowires by Modulation-Doping via Aluminum-Induced Acceptor States in an SiO2-shell — •Daniel Hiller1, Ingmar Ratschinski1, Soundarya Nagarajan2, Jens Trommer2, Thomas Mikolajick2,3, and Dirk König4 — 1Institute of Applied Physics, TU Bergakademie Freiberg, Germany — 2Nanoelectronic Materials Laboratory gGmbH, Dresden, Germany — 3Institute of Semiconductors and Microsystems, TU Dresden, Germany — 4Integrated Materials Design Lab, ANU, Canberra, Australia
Silicon nanowires (Si NWs) enable maximum gate control over the source-drain current when configured in a gate-all-around FET-architecture. However, Si NWs with few nm in diameter suffer from severe difficulties with efficient impurity doping due to a multitude of physical and technological problems (diffusion, dielectric and quantum confinement, statistics of small numbers, etc.). Here, we present a novel doping concept for Si NWs comparable to the modulation doping approach of III-V semiconductors. Based on results from density functional theory (DFT) calculations, we use Al-doped SiO2 shells around the Si NWs, which contain unoccupied Al-induced acceptor states that are energetically located below the Si valence band edge. These states can capture electrons from the Si, creating free holes as majority charge carriers [1-5]. In this presentation, recent results from the experimental realization of this concept on Si NWs are shown. We demonstrate that modulation doping using SiO2:Al-shells allows for several orders of magnitude lower resistances when compared to undoped SiO2-shells. [1] D. König et al., Sci. Rep. 7, 46703 (2017)