Regensburg 2016 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 11: Poster
DF 11.9: Poster
Mittwoch, 9. März 2016, 18:00–20:00, Poster E
Growth of epitaxial Ba2SiO4 on Si(100) — •Min Huang, Julian Koch, Shariful Islam, and Herbert Pfnür — Inst. für Festkörperphysik, Appelstr. 2, 30167 Hannover
In search of an alternative gate oxide Barium silicate thin films on Si(100) were investigated. In order to specify the stoichiometry and band gap of these oxides we used X-ray Photoelectron Spectroscopy (XPS) and Electron Energy Loss Spectroscopy (EELS) respectively. The morphology was controlled by Spot Profile Analysis-Low Energy Electron Diffraction (SPA-LEED). To further investigate the crystalline growth, crystal orientation and thickness High Resolution Transmission Electron Microscopy (HRTEM) was used.
In previous work in our group, we investigated Ba2SiO4, which was grown by depositing a crystalline BaO2 layer on Si(100) and heating the sample to 650 ∘C leading to a diffusion of Si into the BaO2 layer [1]. The silicate was found to be a very promising candidate as an alternative gate dielectric. It has a high temperature stability up to desorption (approx. 720 ∘C), a dielectric constant of 20, a band offset of >2eV and a very low hysteresis of <0.5 mV. But due to the growth process the interface was quite rough and the silicate layer was not completely crystalline as confirmed by HRTEM. Thus, the leakage current was comparatively high (0.1 A/cm2 at 1V). Here we present new results, where we avoid diffusion of Si by co-deposition of Ba and Si in an oxygen atmosphere and show that crystallinity as well as leakage currents were improved.
[1] Islam, S., Ph.D. thesis, Leibniz Universität Hannover (2015)