Browsing by Author "Luo, G. L."

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Fabricating a n(+)-Ge contact with ultralow specific contact resistivity by introducing a PtGe alloy as a contact metal
(2015-09-14)
Hsu, C. C.
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Chou, C. H.
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Wang, S. Y.
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Chi, W. C.
;
Chien, C. H.
In this study, we developed an Ohmic contact structure to an in situ n(+)-Ge film that has an ultralow specific contact resistivity of [(6.8 +/- 2.1) x 10(-8) Omega.cm(2)]. This structure was developed by introducing a PtGe alloy as the contact metal. We observed that Ohmic contact behavior can be achieved with several other metals, and the contact resistance is related to the work function of the metal. A physical model of the band diagram was created for the Schottky tunneling width, which can provide insight into the validation and explanation of work function-dependent specific contact resistivity. Dopant segregation at the interface and increased interface roughness induced by the formation of the alloy are crucial in further reducing the specific contact resistivity. As a result, a stable PtGe alloy and high doping concentration in Ge are critical in pursuing a lower contact resistance for a Ge n-channel device. (C) 2015 AIP Publishing LLC.
Fabricating a n(+)-Ge contact with ultralow specific contact resistivity by introducing a PtGe alloy as a contact metal (vol 107, 113503, 2015)
(2015-12-07)
Hsu, C. C.
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Chou, C. H.
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Wang, S. Y.
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Chi, W. C.
;
Chien, C. H.
Growth and characterization of Ge nanostructures selectively grown on patterned Si
(2008-11-03)
Cheng, M. H.
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Ni, W. X.
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Luo, G. L.
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Huang, S. C.
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Chang, J. J.
By utilizing different distribution of strain fields around the edges of oxide, which are dominated by a series of sizes of oxide-patterned windows, long-range ordered self-assembly Ge nanostructures, such as nano-rings, nano-disks and nano-dots, were selectively grown by ultra high vacuum chemical vapor deposition (UHV-CVD) on Si (001) substrates. High-resolution double-crystal symmetrical omega/2 theta scans and two-dimensional reciprocal space mapping (2D-RSM) technologies employing the triple axis X-ray diffractometry have been used to evaluate the quality and strain status of as-deposited as well as in-situ annealed Ge nanostructures. Furthermore, we also compare the quality and strain status of Ge epilayers grown on planar unpatterned Si substrates. It was found that the quality of all Ge epitaxial structures is improved after in-situ annealing process and the quality of Ge nano-disk structures is better than that of Ge epilayers; on planar unpatterned Si substrates, because oxide sidewalls are effective dislocation sinks. We also noted that the degree of relaxation for as-deposited Ge epilayers on planar unpatterned Si substrates is less than that for as-deposited Ge nano-disk structures. After in-situ annealing process,all Ge epitaxial structures are almost at full relaxation whatever Ge epitaxial structures grew on patterned or unpatterned Si substrates. (c) 2008 Published by Elsevier B.V.
Self-assembled In0.22Ga0.78As quantum dots grown on metamorphic GaAs/Ge/SixGe1-x/Si substrate
(2006-09-15)
Hsieh, Y. C.
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Chang, E. Y.
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Luo, G. L.
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Chen, S. H.
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Biswas, Dhrubes
Self-assembled In0.22Ga0.78As quantum dots (QDs) grown on Si substrate with Ge/SiGe as buffer layer grown by metal organic vapor phase epitaxy were investigated. Transmission electron microscopy and atomic force microscopy images were used to observe the size and space distribution of the In0.22Ga0.78As QDs grown on the GaAs/Ge/GeSi/Si layer structure. The influence of the growth temperature on the QDs size and density distribution was investigated. For QDs grown at 450 degrees C, the density of the In0.22Ga0.78As dots was estimated to be 1x10(11) cm(-2) and the In0.22Ga0.78As QDs thickness was 5 ML (monolayer) thick. (c) 2006 American Institute of Physics.
Use of Si+ pre-ion-implantation on Si substrate to enhance the strain relaxation of the GexSi1-x metamorphic buffer layer for the growth of Ge layer on Si substrate
(2007-02-19)
Hsieh, Y. C.
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Chang, E. Y.
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Luo, G. L.
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Pilkuhn, M. H.
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Tang, S. S.
Si+ pre-ion-implantation combined with a GexSi1-x metamorphic buffer structure for the growth of Ge layer on Si substrate is proposed. Enhanced strain relaxation of the GexSi1-x metamorphic buffer layer on Si substrate was achieved due to the introduction of the point defects by heavy dose Si+ pre-ion-implantation. Because of the strain relaxation enhancement and the interface blocking of the dislocations in the GexSi1-x metamorphic buffer structure, the total thickness of the buffer layers was only 0.45 mu m. No cross-hatch pattern was observed on the Ge surface and the dislocation density for the top Ge film was only 7.6x10(6) cm(-2). (c) 2007 American Institute of Physics.