Browsing by Author "Zeng, Hung-Yu"

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Comparison between extended microtunnels along different crystal orientations in GaN
(2008)
Wu, Pei-Lun
;
Huang, Hsin-Hsiung
;
Zeng, Hung-Yu
;
Liu, Po-Chun
;
Lai, Chih-Ming
Triangular prism-like extended microtunnels (EMTs) can be easily formed in specially designed cpitaxial lateral overgrowth GaN thick films by selective wet chemical etching in molten potassium hydroxide (KOH), In this study, extended microtunnels along the < 1100 > and the < 1120 > directions were fabricated and compared. If tunnels along the < 1100 > direction, the (1122) planes would be the etch stop plane. While the tunnels along < 1120 > direction, the etch stop plane would become to (1011) planes. The activation energies of wet chemical etch for the {1122} planes and the (1011) planes were determined to be 23.6 kcal/mol (1.02 eV) and 22.8 kcal/mol (0.99 eV) using Arrhenius plot. On the other hand, the etching depths of the tunnels along the < 1100 > direction were more than twice the depths of the tunnels along the < 1120 > direction during the same etching time. The highest etch rate of the tunnels along the axial direction can reach 1000 mu m/hr in < 1100 > direction, which is believed to be the highest etch rate of GaN ever reported. Additional crystal facet of m-plane in GaN was also observed in the sample with extended microtunnels along the < 1120 > direction. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Etching method for nitride semiconductor
(2009-03-05)
Lee, Wei-I
;
Huang, Hsin-Hsiung
;
Zeng, Hung-Yu
The invention discloses etching method for the nitride semiconductor. Firstly dielectric layer is formed on gallium nitride. The line pattern or dot pattern is formed on the dielectric layer by using the exposure, development, and etching processes. The dielectric layer is used as the mask for the epitaxial lateral overgrowth of follow-up gallium nitride layer. The thick gallium nitride film is grown on the dielectric layer. Then the wet etching process is used to remove the dielectric layer, and the thick gallium nitride film on the dielectric layer is etched to form the specific shape as required.
Extended microtunnels in GaN prepared by wet chemical etch
(2006-11-13)
Huang, Hsin-Hsiung
;
Zeng, Hung-Yu
;
Lee, Chi-Ling
;
Lee, Shih-Chang
;
Lee, Wei-I
It is demonstrated in GaN that microtunnels extended beyond hundreds of microns can be easily achieved using wet chemical etch. To obtain this result, specially designed structures of GaN layers are first grown on sapphire substrates with metal-organic chemical vapor deposition and subsequently with hydride vapor phase epitaxy techniques. The prepared samples are then chemically etched in molten KOH. With the designed structure of GaN layers, extended microtunnels with triangular cross sections are formed. The crystallographic planes of the triangular bevels belong to the {11(2) over bar 2} family. The etch rate of the tunnel can be as high as 10 mu m/min at proper etching conditions. (c) 2006 American Institute of Physics.
Preparation of extended microtunnels in GaN by wet chemical etching
(2007-06-01)
Huang, Hsin-Hsiung
;
Zeng, Hung-Yu
;
Lee, Wei-I
;
電子物理學系
;
Department of Electrophysics
Extended microtunnels with triangular cross sections are demonstrated in GaN layers on sapphire substrates. The depths of the tunnels can easily reach several hundred micrometers by using wet chemical etching. To obtain this result, patterned growth of specially designed GaN layers is carried out on sapphire substrates with metalorganic chemical vapor deposition and subsequently hydride vapor-phase epitaxy techniques. The prepared samples are then chemically etched in molten potassium hydroxide, and microtunnels with triangularly etched cross sections are formed. The planes of the triangular bevels belong to the {11 (2) over bar2} family. The etch rate of the tunnel can be as high as 10 mu m/min under proper etching conditions. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Triangular extended microtunnels in GaN prepared by selective crystallographic wet chemical etching
(2008)
Huang, Hsin-Hsiung
;
Wu, Pei-Lun
;
Zeng, Hung-Yu
;
Liu, Po-Chun
;
Chi, Tung-Wei
Extended microtunnels with triangular cross sections in thick GaN films were demonstrated using wet chemical etching on specially designed epitaxial lateral overgrowth structures. For tunnels along the < 1 (1) over bar 00 > and < 11 (2) over bar0 > directions of GaN, the {11 (22) over bar} and {10 (11) over bar} facets are the etch stop planes with activation energies of 23 kcal/mol determined by wet chemical etching. The axial etching rate of the tunnels in the < 1 (1) over bar 00 > direction is twice as large than that along the < 11 (2) over bar0 > direction. The highest etching rate of the tunnels in the axial direction is 1000 mu m/h. (C) 2008 The Electrochemical Society.