Modulation Doping of Silicon Nanowires to Tune the Contact Properties of Nano‐Scale Schottky Barriers

Autor: Soundarya Nagarajan, Daniel Hiller, Ingmar Ratschinski, Dirk König, Sean C. Smith, Thomas Mikolajick, Jens Trommer
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Advanced Materials Interfaces, Vol 11, Iss 1, Pp n/a-n/a (2024)
Druh dokumentu: article
ISSN: 2196-7350
20230060
DOI: 10.1002/admi.202300600
Popis: Abstract Doping silicon on the nanoscale by the intentional introduction of impurities into the intrinsic semiconductor suffers from effects such as dopant deactivation, random dopant fluctuations, out‐diffusion, and mobility degradation. This paper presents the first experimental proof that doping of silicon nanowires can also be achieved via the purposeful addition of aluminium‐induced acceptor states to the SiO2 shell around a silicon nanowire channel. It is shown that modulation doping lowers the overall resistance of silicon nanowires with nickel silicide Schottky contacts by up to six orders of magnitude. The effect is consistently observed for various channel geometries and systematically studied as a function of Al2O3 content during fabrication. The transfer length method is used to separate the effects on the channel conductivity from that on the barriers. A silicon resistivity is achieved as low as 0.04–0.06 Ω ·cm in the nominal undoped material. In addition, the specific contact resistivity is also strongly influenced by the modulation doping and reduced down to 3.5E‐7 Ω · cm2, which relates to lowering the effective Schottky barrier to 0.09 eV. This alternative doping method has the potential to overcome the issues associated with doping and contact formation on the nanoscale.
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