Browsing by Subject "A1. Defects"

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    Effect of growth pressure on coalescence thickness and crystal quality of GaN deposited on 4H-SiC
    (Elsevier, 2010-09-25) Caban, P.; Strupinski, W.; Szmidt, J.; Wojcik, M.; Gaca, J.; Kelekci, O.; Caliskan, D.; Özbay, Ekmel
    The influence of growth pressure on the coalescence thickness and the crystal quality of GaN deposited on 4HSiC by low pressure metalorganic vapor phase epitaxy was studied. It was shown that growth pressure has an impact on the surface roughness of epilayers and their crystal quality. GaN coalescence thicknesses were determined for the investigated growth pressures. The GaN layers were characterized by AFM and HRXRD measurements. HEMT structures were also fabricated and characterized. Among the growth pressures studied, 50, 125 and 200 mbar, 200 mbar was found to be most suitable for GaN/SiC epitaxy.
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    Lateral overgrowth of germanium for monolithic integration of germanium-on-insulator on silicon
    (Elsevier, 2015) Hyung Nam J.; Alkis, S.; Nam, D.; Afshinmanesh F.; Shim J.; Park, J.; Brongersma, M.; Okyay, Ali Kemal; Kamins, T.I.; Saraswat, K.
    A technique to locally grow germanium-on-insulator (GOI) structure on silicon (Si) platform is studied. On (001) Si wafer, silicon dioxide (SiO2) is thermally grown and patterned to define growth window for germanium (Ge). Crystalline Ge is grown via selective hetero-epitaxy, using SiO2 as growth mask. Lateral overgrowth of Ge crystal covers SiO2 surface and neighboring Ge crystals coalesce with each other. Therefore, single crystalline Ge sitting on insulator for GOI applications is achieved. Chemical mechanical polishing (CMP) is performed to planarize the GOI surface. Transmission electron microscopy (TEM) analysis, Raman spectroscopy, and time-resolved photoluminescence (TRPL) show high quality crystalline Ge sitting on SiO2. Optical response from metal-semiconductor-metal (MSM) photodetector shows good optical absorption at 850 nm and 1550 nm wavelength. © 2015 Elsevier B.V. All rights reserved.