Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral - Tesis

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Browsing Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral - Tesis by Author "Gorji, Mohammad Saleh"

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    Fabrication And Characterization Of Embedded Gold Nanoparticles In Metal Contacts For Silicon And Silicon Carbide-Based Devices
    (2014-06)
    Gorji, Mohammad Saleh
    Embedding metal nanoparticles (NPs) into metal contacts, at the interface with semiconductor, is an alternative method for modification of Schottky barrier height (SBH) in electrical contacts and offers a tremendous simplification and adaptation in processing steps. Schottky barrier diodes with aluminum (Al) contacts embedded with gold (Au) NPs on n- and p-type silicon (Si) and silicon carbide (4H-SiC) substrates were fabricated and their physical and electrical characteristics were investigated. Based on the studies on Si surface contact angle measurement and the negative zeta-potential values of seeded growth 20 nm Au NPs, an alternative approach was proposed to deposit Au NPs on linker-free n- and p-Si substrates using spin-coating technique. Density of NPs (determined by scanning electron microscope) on n-Si was substantially higher than p-Si which was due to the differences in surface properties of n- and p-Si. Current-voltage analysis of diodes revealed an increase in current density in both bias directions due to NPs local electric field enhancement effect and SBH lowering (0.1 1 eV for n- and 0.05 eV for p-Si). The electrical results were then correlated to the structural properties of Al/Si (determined by transmission electron microscope). Higher density of 5 and 10 nm Au NPs were deposited on SiC surface by using acidification technique with diluted HF. Al/4H-SiC diodes showed great improvement in SBH lowering (0.09 eV for n- and 0.24 eV for p-4H-SiC) and hence forward bias current density elevation while maintaining the rectification properties in reverse bias.