Browsing by Author "Tang, Shih-Hsuan"

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Effect of Low Temperature Ge Seed Layer and Post Thermal Annealing on Quality of Ge1-xSix (0.05 <= x <= 0.1) Graded Buffer Layers by UHV-CVD
(2014-07-01)
Chi-Lang Nguyen
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Nguyen Hong Quan
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Binh-Tinh Tran
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Su, Yung-Hsuan
;
Tang, Shih-Hsuan
High crystal quality, smooth surface and fully relaxed Ge1-xSix (0.05 <= x <= 0.1) buffers are grown on 6 degrees-off (100) Si substrate by UHV-CVD. A low-temperature (LT) Ge seed layer is used to improve the quality of the Ge1-xSix buffers. In this study, the LT-Ge seed layer is deposited directly onto the Si substrate at a low temperature of 315 degrees C. After that, stress-free Si0.1Ge0.9 and Si0.05Ge0.95 layers are grown, respectively. An in-situ annealing process is also performed for the Si0.1Ge0.9/LT-Ge layers to increase the degree of relaxation. The total thickness of the epitaxial layer is 270 nm, with the average surface roughness at 0.6 nm.
Ge epitaxial films on GaAs (100), (110), and (111) substrates for applications of CMOS heterostructural integrations
(2013-03-01)
Tang, Shih-Hsuan
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Kuo, Chien-I
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Trinh, Hai-Dang
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Chang, Edward Yi
;
Nguyen, Hong-Quan
Epitaxial Ge films were grown on GaAs (100), (110), and (111) substrates by using ultra-high vacuum chemical vapor deposition and studied with various methods. The incubation times and growth rates were quite different for these three GaAs substrates because the surface arsenic coverage on GaAs and hydrogen desorption energy on Ge are different for each orientation. High-resolution x-ray diffraction measurements, direct band-gap emission of photoluminescence measurements, and cross-sectional transmission electron microscopy showed that the Ge films had high crystal quality, low defect density, and sharp Ge/GaAs interfaces. In this study, atomic force microscopy analysis found that the Ge films grow on GaAs (100) and (111) via the Frank van der Merwe mode, while the Ge film grows on GaAs (110) via the Volmer-Weber mode at the initial growth stage, which can be explained by the thermodynamic theory of capillarity. Interestingly, when the thickness of the Ge film on the GaAs (110) substrate increases to similar to 220 nm, the 3D Ge islands merge and form a smooth surface (rms roughness of 0.3 nm), which is useful for devices. The authors also fabricated Ge metal-oxide-semiconductor capacitors (MOSCAPs) on GaAs (100) and (110) substrates. Both Ge/GaAs (100) and Ge/GaAs (110) MOSCAPs exhibit good capacitance-voltage responses with strong inversion behaviors, which means the grown material has reached device quality. The Ge/GaAs (110) structure especially offers optimal integration of Ge pMOSFETs on GaAs substrates because Ge (110) has a high hole mobility compared with Ge (100) and (111). (C) 2013 American Vacuum Society. [http://dx.doi.org/10.1116/1.4789427]
High Quality Ge Epitaxial Films Grown on In0.51Ga0.49P/GaAs and GaAs Substrates by Ultra High Vacuum Chemical Deposition
(2014-01-01)
Su, Yung-Hsuan
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Tang, Shih-Hsuan
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Nguyen, Chi Lang
;
Kuan, Ching-Wen
;
Yu, Hung-Wei
The epitaxial growth of high quality Ge thin films on different materials of In0.51Ga0.49P and GaAs by ultra high vacuum chemical vapor deposition (UHVCVD) system was studied. The crystallinity of high quality Ge layers on In0.51Ga0.49P and GaAs layers can be proved by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The comparison of surface morphology between Ge grown on In0.51Ga0.49P and GaAs was also analyzed by atomic force microscopy (AFM). The roughness of Ge on GaAs shows better than that of In0.51Ga0.49P. Both of these structures were designed for fabricating p-channel metal-oxide-semiconductor field-effect transistor (MOSFET) for the integration of Ge p-channel device with III-V n-channel electronic device.
High quality Ge thin film grown by ultrahigh vacuum chemical vapor deposition on GaAs substrate
(2011-04-18)
Tang, Shih-Hsuan
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Chang, Edward Yi
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Hudait, Mantu
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Maa, Jer-Shen
;
Liu, Chee-Wee
High-quality epitaxial Ge films were grown on GaAs substrates by ultrahigh vacuum chemical vapor deposition. High crystallinity and smooth surface were observed for these films by x-ray diffraction, transmission electron microscopy, and atomic force microscopy. Direct band gap emission (1550 nm) from this structure was detected by photoluminescence. Valence band offset of 0.16 eV at the Ge/GaAs interface was measured by x-ray photoelectron spectroscopy. N-type arsenic self-doping of 10(18)/cm(-3) in the grown Ge layers was determined using electrochemical capacitance voltage measurement. This structure can be used to fabricate p-channel metal-oxide-semiconductor field-effect transistor for the integration of Ge p-channel device with GaAs n-channel electronic device. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580605]
Method for forming a GexSi1-x buffer layer of solar-energy battery on a silicon wafer
(2010-05-27)
Chang, Edward Yi
;
Tang, Shih-Hsuan
;
Lin, Yue-Cin
The method is disclosed that Si+ is implanted on Si substrate to enhance strain relaxation at the interface between the metamorphic GexSi1−x buffer layers and Si substrate, in order to facilitate the growth of a high quality Ge on Si substrate. And several GexSi1−x buffer layers (Si/Ge0.8Si0.2/Ge0.9Si0.1/Ge) are grown on top of Si substrate by UHVCVD. Then grow pure Ge layer of low dislocation density on GexSi1−x buffer layer. Finally, grow up high efficiency III-V solar cell on GexSi1−x buffer layer.
Study of the inversion behaviors of Al(2)O(3)/In(x)Ga(1-x)As metal-oxide-semiconductor capacitors with different In contents
(2010-01-01)
Wu, Yun-Chi
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Chang, Edward Yi
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Lin, Yueh-Chin
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Kei, Chi-Chung
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Hudait, Mantu K.
In(x)Ga(1-x)As III-V compound semiconductor metal-oxide-semiconductor field-effect transistors have become a popular topic recently due to the higher drift velocity, and lower effective mass of the In(x)Ga(1-x)As materials. The impact of In content on the accumulation and inversion behaviors of the Al(2)O(3)/In(x)Ga(1-x)As capacitors is investigated in this study. For the various In(x)Ga(1-x)As materials studied, the Al(2)O(3)/InAs MOS system showed the strongest inversion phenomena due to the shorter response time of minority carrier of InAs compared to other In(x)Ga(1-x)As materials. Also, very low gate leakage current in the 10(-8) A/cm(2) range was observed for these capacitors. These results demonstrate that Al(2)O(3)/InAs MOS system with strong inversion phenomena and low leakage gate current is potential candidate for future high-performance low power logic MOSFET applications. (C) 2009 Elsevier Ltd. All rights reserved.
Study of the inversion behaviors of Al2O3/InxGa1-xAs metal-oxide-semiconductor capacitors with different In contents
(2010-01-01)
Wu, Yun-Chi
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Chang, Edward Yi
;
Lin, Yueh-Chin
;
Kei, Chi-Chung
;
Hudait, Mantu K.
InxGa1-xAs III-V compound semiconductor metal-oxide-semiconductor field-effect transistors have become a popular topic recently due to the higher drift velocity, and lower effective mass of the InxGa1-xAs materials. The impact of In content on the accumulation and inversion behaviors of the Al2O3/InxGa1-xAs capacitors is investigated in this study. For the various InxGa1-xAs materials studied, the Al2O3/InAs MOS system showed the strongest inversion phenomena due to the shorter response time of minority carrier of InAs compared to other InxGa1-xAs materials. Also, very low gate leakage current in the 10(-8) A/cm(2) range was observed for these capacitors. These results demonstrate that Al2O3/InAs MOS system with strong inversion phenomena and low leakage gate current is potential candidate for future high-performance low power logic MOSFET applications. (C) 2009 Elsevier Ltd. All rights reserved.
The Materials Integration of Ge and InxGa1-xAs on Si Template for Next Generation CMOS Applications
(2013)
Chang, Edward Yi
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Tang, Shih-Hsuan
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Lin, Yueh-Chin
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材料科學與工程學系
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Department of Materials Science and Engineering
In the study, the growth of InAs on Si is demonstrated using "interface blocking" technique with SiGe layers as buffer layer. the growth of high quality Ge film on GaAs substrate by ultra high vacuum chemical vapor deposition and high quality InAs material on Ge/SiGe/Si template grown by molecular beam epitaxy will be particularly reported. By the observation of XRD and AFM, both Ge film grown on GaAs material and InAs grown on Si substrates demonstrate high crystallinity and good surface morphology. The developed epitaxial materials systems including Ge on GaAs and InAs on Si are useful for future III-V/Ge/Si integration for next generation high speed low power CMOS application as well as for RF/digital mixed signal circuit application in the future.