Browsing by Subject "Low defect densities"

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    High quality single-crystal germanium-on-insulator on bulk Si substrates based on multistep lateral over-growth with hydrogen annealing
    (American Institute of Physics, 2010-08-09) Yu, H. Y.; Cheng, S. L.; Park, J. H.; Okyay, Ali Kemal; Onbal, M. C.; Ercan, B.; Nishi, Y.; Saraswat, K. C.
    Germanium-on-insulator (GOI) is desired for high performance metal-oxide-semiconductor transistors and monolithically integrated optoelectronics. We demonstrate a promising approach to achieve single-crystal defect-free GOI by using lateral over-growth through SiO2 window. The dislocations due to the lattice mismatch are effectively terminated and reduced in SiO2 trench by selective area heteroepitaxy combined with hydrogen annealing. Low defect density of 4× 106 cm-2 and low surface roughness of 0.7 nm (root-mean-square) on GOI are confirmed by plan-view transmission electron microscopy and atomic force microscopy analysis. In addition, the excellent metal-semiconductor-metal diode electrical characteristics fabricated on this GOI confirm Ge crystal quality. The selectively grown GOI structure can provide the monolithic integration of SiGe based devices on a Si very large scale integration (VLSI) platform
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    Selective-area high-quality germanium growth for monolithic integrated optoelectronics
    (Institute of Electrical and Electronics Engineers, 2012-03-02) Yu, H. Y.; Park, J. H.; Okyay, Ali Kemal; Saraswat, K. C.
    Selective-area germanium (Ge) layer on silicon (Si) is desired to realize the advanced Ge devices integrated with Si very-large-scale-integration (VLSI) components. We demonstrate the area-dependent high-quality Ge growth on Si substrate through SiO 2 windows. The combination of area-dependent growth and multistep deposition/hydrogen annealing cycles has effectively reduced the surface roughness and the threading dislocation density. Low root-mean-square surface roughness of 0.6 nm is confirmed by atomic-force-microscope analysis. Low defect density in the area-dependent grown Ge layer is measured to be as low as 1 × 10 7cm -2 by plan-view transmission-electron-miscroscope analysis. In addition, the excellent metal-semiconductor-metal photodiode characteristics are shown on the grown Ge layer to open up a possibility to merge Ge optoelectronics with Si VLSI.