Browsing by Author "Hsu, Ching Yi"

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C-V characteristics of epitaxial germanium metal-oxide-semiconductor capacitor on GaAs substrate with ALD Al2O3 dielectric
(2012-09-01)
Tang, Shih Hsuan
;
Kuo, Chien I.
;
Hai Dang Trinh
;
Hudait, Mantu
;
Chang, Edward Yi
Epitaxial germanium metal-oxide-semiconductor capacitors (MOSCAP) were fabricated on GaAs substrate using atomic layer deposited Al2O3 gate dielectric with surface treatments including pure HF and HF plus rapid thermal oxidation (RTO). The electrical characteristics of 10 nm Al2O3/Ge MOSCAP showed p-type behavior with excellent C-V responses and low leakage current. Interface state density in the order of 10(11) eV(-1) cm(-2) was determined from the conductance method and the HF plus RTO treatment exhibits better Al2O3/Ge interface quality than that of pure HF treatment. (C) 2012 Elsevier B.V. All rights reserved.
Effect of Two-Step Metal Organic Chemical Vapor Deposition Growth on Quality, Diameter and Density of InAs Nanowires on Si (111) Substrate
(2018-02-01)
Yu, Hung Wei
;
Anandan, Deepak
;
Hsu, Ching Yi
;
Hung, Yu Chih
;
Su, Chun Jung
High-density (similar to 80/um(2)) vertical InAs nanowires (NWs) with small diameters (similar to 28 nm) were grown on bare Si (111) substrates by means of two-step metal organic chemical vapor deposition. There are two critical factors in the growth process: (1) a critical nucleation temperature for a specific In molar fraction (approximately 1.69 x 10(-5) atm) is the key factor to reduce the size of the nuclei and hence the diameter of the InAs NWs, and (2) a critical V/III ratio during the 2nd step growth will greatly increase the density of the InAs NWs (from 45 mu m(-2) to 80 mu m(-2)) and at the same time keep the diameter small. The high-resolution transmission electron microscopy and selected area diffraction patterns of InAs NWs grown on Si exhibit a Wurtzite structure and no stacking faults. The observed longitudinal optic peaks in the Raman spectra were explained in terms of the small surface charge region width due to the small NW diameter and the increase of the free electron concentration, which was consistent with the TCAD program simulation of small diameter (< 40 nm) InAs NWs.
The integration of Ge and III-V materials on GaAs and Si for Post CMOS applications
(2012)
Chang, Edward Yi
;
Chang, Chia Hua
;
Tang, Shih Hsuan
;
Hai Dang Trinh
;
Kuo, Chien I.
In the study, the growth of InAs on Si is demonstrated using "interface blocking" technique with SiGe layers as buffer layer. And the growth of high quality Ge film on GaAs is demonstrated using ultra high vacuum chemical vapor deposition (UHVCVD). Both Ge film grown on GaAs and InAs film grown on Si substrate demonstrate high crystallinity and good surface morphology as observed by XRD and AFM. Furthermore, the fabrication process and electric characteristics of Ge/GaAs and InAs/Si is discussed in the study. The developed epitaxial materials systems and device fabrication including InAs on Si, Ge on GaAs are useful for future III-V and Ge integration on Si substrate for next generation high speed low power CMOS as well as for RF/digital mixed signal circuit applications in the future.