AVS 53rd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoA

Paper EM-MoA7
Tuning the Schottky Barrier Height in Mg/Si Diodes

Monday, November 13, 2006, 4:00 pm, Room 2003

Session: Contacts, Interfaces and Defects in Semiconductors
Presenter: H. Nienhaus, University of Duisburg-Essen, Germany
Authors: H. Nienhaus, University of Duisburg-Essen, Germany
S. Glass, University of Duisburg-Essen, Germany
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Thin metal film Mg/p-Si(111) Schottky diodes have been successfully used for sensing of chemically induced electron-hole pairs.@footnote 1@ Controlled variation of the homogeneous Schottky barrier height allows to probe the energy distribution of hot charge carriers. Different types of Mg/p-Si diodes were prepared by thermal evaporation of thin Mg layers on H-passivated Si(111) surfaces at low temperatures followed by various annealing procedures. After deposition at 190 K, the current-voltage characteristics of the diodes are typical for interfaces with lateral inhomogeneity and high ideality factors. The homogeneous barrier height is measured as 0.8 eV. This value is much larger than expected from theory of metal-induced gap states. The deviation is explained by interface dipoles due to the monatomic hydrogen layer between Mg and Si. The hydrogen is removed by annealing the diodes to room temperature. This procedure leads to the formation of an intermediate Mg silicide layer and to a significant reduction of the barrier height. The annealed diodes exhibit excellent current-voltage properties. Applications of the diodes for chemical sensing (chemicurrents) and for internal photoemission are discussed. @FootnoteText@ @footnote 1@ S. Glass, H. Nienhaus, Phys. Rev. Lett. 93 (2004) 168302.