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

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Soundarya Nagarajan - , Chair of Nanoelectronics, NaMLab - Nanoelectronic materials laboratory gGmbH (Author)
  • Daniel Hiller - , Freiberg University of Mining and Technology (Author)
  • Ingmar Ratschinski - , Freiberg University of Mining and Technology (Author)
  • Dirk König - , Australian National University (Author)
  • Sean C. Smith - , Australian National University (Author)
  • Thomas Mikolajick - , Chair of Nanoelectronics, NaMLab - Nanoelectronic materials laboratory gGmbH (Author)
  • Jens Trommer - , Faculty of Electrical and Computer Engineering, NaMLab - Nanoelectronic materials laboratory gGmbH (Author)

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.

Details

Original languageEnglish
Article number2300600
Number of pages8
JournalAdvanced materials interfaces
Volume11(2024)
Issue number1
Publication statusPublished - 31 Oct 2023
Peer-reviewedYes

External IDs

Mendeley a5c1cf6f-f4eb-38ae-ba9a-430bbed5523d
WOS 001082641900001
ORCID /0000-0003-3814-0378/work/146646235

Keywords

DFG Classification of Subject Areas according to Review Boards

Subject groups, research areas, subject areas according to Destatis

Keywords

  • contact resistance, modulation doping, nickel silicide, Schottky barrier height, silicon nanowires, transfer length method, Transfer length method, Nickel silicide, Contact resistance, Modulation doping, Silicon nanowires