Browsing by Author "Chiu, Kun-An"

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Defects in semipolar (11(2)over-bar(2)over-bar) ZnO grown on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 substrate by pulsed laser deposition
(2013-03-27)
Tian, Jr-Sheng
;
Wu, Yue-Han
;
Peng, Chun-Yen
;
Chiu, Kun-An
;
Shih, Yi-Sen
The microstructure of semipolar (11 (2) over bar(2) over bar) ZnO deposited on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 was investigated by transmission electron microscopy. The ZnO shows an in-plane epitaxial relationship of [11 (2) over bar3](ZnO) parallel to [11 (1) over bar](LAO/LSAT) with oxygen-face sense polarity. The misfit strain along [11 (2) over bar3](ZnO) and [1 (1) over bar 00](ZnO) is relieved through the formation of misfit dislocations with the Burgers vectors b = 1/6[11 (2) over bar3](ZnO) and b = 1/3 < 1 (2) over bar 10 >(ZnO), respectively. The line defects in the semipolar ZnO are predominantly perfect dislocations, and the dislocation density decreases with increasing ZnO thickness as a result of dislocation reactions. Planar defects were observed to lie in the M-plane and extend along < 0001 >, whereas basal stacking faults were rarely found.
Formation of m-plane AlN on plasma-nitrided m-plane sapphire
(2019-06-01)
Ma, Zhih-Cheng
;
Chiu, Kun-An
;
Wei, Lin-Lung
;
Chang, Li
;
材料科學與工程學系
Microwave plasma using a gas mixture of N-2 and H-2 has been applied for the nitridation of m-plane sapphire substrate to form a thick epitaxial AlN film. The X-ray diffraction results show that the AlN films formed on the sapphire surface by nitridation for a period from 10-60 min are in (1010) orientation and have an epitaxial relationship with the substrate. The thickness of the nitride film increases with nitridation time and approaches about 0.5 mu m after nitridation for 1 h, while the film surface becomes rough. The film quality is reasonably good, as evaluated with the X-ray rocking curve of (1010) AlN. Faceted voids in the sapphire substrate underneath the AlN are also observed with inclined a-plane facets after nitridation. (C) 2019 The Japan Society of Applied Physics
Heteroepitaxial growth and microwave plasma annealing of DC reactive sputtering deposited TiZrN film on Si (100)
(2020-07-25)
Chiu, Kun-An
;
Fu, Chia-Wei
;
Fang, Yu-Siang
;
Thi Hien Do
;
Shih, Fu-Han
Epitaxial TiZrN films were successfully grown on Si (100) substrates at high temperature by using DC magnetron reactive sputtering with a Ti0.68Zr0.32 alloy target. Annealing of a grown TiZrN/Si specimen was performed by applying microwave plasma with a gas mixture of N-2 and H-2 to improve the film quality. The X-ray rocking curve (XRC) width of (200)(TiZrN) reflection can reach a minimum value of 1.18 degrees. The heteroepitaxial relationship of TiZrN with Si is {001}(TiZrN)//{001}(Si) and < 110 >(TiZrN)//< 110 >(Si). The (200)(TiZrN) XRC width of a 20 nm-thick TiZrN film reduces from 1.99 degrees to 0.85 degrees by microwave plasma annealing. As a result of the improvement of the film quality, the annealed film exhibits a much lower resistivity (28 mu Omega.cm) than that of the as-deposited one (44 mu Omega.cm). The surface morphologies of the TiZrN films are smooth with the surface roughness in the range of 1-2 nm.
Oriented Si3N4 crystallites formed by plasma nitriding of SiO2/Si (111) substrate
(2020-08-15)
Yu, Chang-Hua
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Chiu, Kun-An
;
Do, Thi-Hien
;
Chang, Li
;
材料科學與工程學系
We show that formation of oriented Si3N4 crystallites can be obtained by plasma nitriding of 20 nm thick SiO2 amorphous layer on Si (111) wafer. Nitriding is achieved at temperature in the range of 800-1000 degrees C with microwave plasma using gas mixture of N-2 and H-2. Results of x-ray diffraction and Raman spectroscopy show that both alpha-Si3N4 and beta-Si3N4 are formed on the nitrided substrate and are strongly oriented in {1 (1) over bar 00} for both phases. The morphologies of the nitrided surfaces as shown by scanning electron microscopy exhibit elongated Si3N4 crystallites aligned with Si < 110 >. Cross-sectional transmission electron microscopy image reveals that the Si3N4/Si interface is sharp without residual SiO2.
Reactive Sputtering Deposition of Epitaxial TiC Film on Si (100) Substrate
(2020-07-01)
Fang, Yu-Siang
;
Thi Hien Do
;
Chiu, Kun-An
;
Chen, Wei-Chun
;
Chang, Li
Epitaxial (100) TiC film deposition on Si (100) substrate by direct current magnetron reactive sputtering of a metallic Ti target with 3%-6% CH4 in Ar gas was investigated. X-ray diffraction and cross-sectional scanning transmission electron microscopy (STEM) reveal that epitaxial cubic TiC can be grown on the Si substrate by domain matching epitaxy in 5/4 ratio with the epitaxial relationship of TiC (100)[0 (1) over bar1] // Si (100)[0 (1) over bar 1]. For sputtering with 3% and 4% CH4, the deposited films are found to consist of both TiC and metallic Ti phases. Increasing the CH4 flow ratio to 5% results in a deposited film completely consisting of TiC without metallic Ti phase. The crystallinity of the deposited TiC is also improved with increasing the CH4 ratio to 5%. X-ray photoelectron spectroscopy shows that the [C]/[Ti] atomic ratio in TiC is nearly close to 1 for growth with 5% CH4 flow ratio and above. The measured electrical resistivities of the deposited films also increase from 41 to 153 mu omega center dot cm with increasing the CH4 ratio from 3% to 6%. With film growth beyond 50 nm thickness, it is shown that some disoriented TiC grains are formed.
Reactive sputtering for highly oriented HfN film growth on Si (100) substrate
(2019-11-15)
Fang, Yu-Siang
;
Chiu, Kun-An
;
Do, Hien
;
Chang, Li
;
材料科學與工程學系
Highly oriented cubic (100) HfN films were grown on Si (100) substrates by direct current magnetron reactive sputtering of a metallic Hf target in an Ar/N-2 gas environment. The influence of N-2 flow ratio on the (100) preferred orientation and crystallinity of the HfN films is investigated. X-ray diffraction shows that not only HEN but also orthorhombic HfSi2 forms in the sputtered films. Increasing the N-2 flow ratio is unfavorable for the formation of HfSi2 while the deposition rate of HfN is decreased. X-ray diffraction and cross-sectional scanning transmission electron microscopy (STEM) reveal that epitaxial orthorhombic HfSi2 can form on the Si substrate, and (100) HfN is in epitaxy with the epitaxial HfSi2. As a result, a (100) oriented HfN film can grow on Si. The epitaxial relationships are shown to be HfN (100)[01 (1) over bar] // HfSi2 (020)[001] // Si (100)[01 (1) over bar] and HfN (100)[01 (1) over bar] // HfSi2 (020)[100] // Si (100)[01 (1) over bar]. Atomically resolved STEM images also show the bonding characteristics across the HfN/HfSi2 and HfSi2/Si interfaces.
Semipolar (11(2)over-bar(2)over-bar) ZnO thin films grown on LaAlO3-buffered LSAT (112) single crystals by pulsed laser deposition
(2013-04-01)
Tian, Jr-Sheng
;
Peng, Chun-Yen
;
Wang, Wei-Lin
;
Wu, Yue-Han
;
Shih, Yi-Sen
Semipolar (11 (2) over bar(2) over bar) ZnO was successfully grown on (112) LaAlO3/(LaAlO3)(0.29)(Sr2AlTaO6)(0.35) substrate by pulsed laser deposition. The epitaxial relationship is [11 (2) over bar3](ZnO)// [11 (1) over bar](LAO/LSAT) with the polar axis of [000 (1) over bar](ZnO) pointing to the surface. For ZnO films with thickness of 1.6 mu m, the threading dislocation density is similar to 1 x 10(9) cm(-2), and the density of basal stacking faults is below 1 x 10(4) cm(-1). The (11 (2) over bar(2) over bar) ZnO exhibits strong (DX)-X-0 emissions with a FWHM of 9 meV and very few green-yellow emissions in the low-temperature (10 K) and room-temperature photoluminescence spectra, respectively. The XRD 2 theta-theta pattern of 1.6 mu m ZnO films grown on (112) LaAlO3/LSAT only reveals a sharp (11 (2) over bar(2) over bar) ZnO reflection for ZnO. The inset figure is the XRD rocking curve of (11 (2) over bar(2) over bar) ZnO with a FWHM of 0.084 degrees. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
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Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
;
Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Stress reduction of (111) homoepitaxial diamond films on nickel-coated substrate
(2014-11-25)
Chiu, Kun-An
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Tian, Jr-Sheng
;
Wu, Yue-Han
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Peng, Chun-Yen
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Chang, Li
Crack-free (111) homoepitaxial diamond films were grown on Ni-coated diamond substrates by microwave plasma chemical vapor deposition. After diamond deposition, the Ni islands with a size of 50-1000 nm were formed and embedded underneath the diamond films. The tensile stress in the diamond films evaluated with micro-Raman spectroscopy can be significantly reduced with the embedded Ni islands, which allows the growth of similar to 5 mu m thick crack-free (111) homoepitaxial diamond films with a good quality, compared with those directly deposited on substrates without coating. (c) 2014 Elsevier B.V. All rights reserved.
Structural property of m-plane ZnO epitaxial film grown on LaAlO(3) (112) substrate
(2010-04-01)
Wang, Wei-Lin
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Ho, Yen-Teng
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Chiu, Kun-An
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Peng, Chun-Yen
;
Chang, Li
The microstructure of m-plane (1 0 (1) over bar 0) ZnO grown on LaAlO(3) (1 1 2) (LAO (1 1 2)) substrate by pulsed laser deposition method has been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD shows that ZnO grown on LAO(1 1 2) appears to be oriented in pure m-plane. TEM electron diffraction patterns in cross section illustrate that m-plane ZnO is in epitaxy with LAO (1 1 2), and the orientation relationships are determined to be [1 (2) over bar 1 0](ZnO)//[(1) over bar (1) over bar 1 ](LAO) and [0 0 0 1](ZnO)//[(1) over bar 1 0](LAO). Also, TEM shows that most of threading dislocations (TDs) in a-type are mainly distributed as wiggle-like lines. From the observations in plan-view TEM, the densities of TDs and basal stacking faults are approximately estimated to be 5.1 x 10(10) cm(-2) and 4.3 x 10(5) cm(-1), respectively. (C) 2009 Elsevier B.V. All rights reserved.
Structural property of m-plane ZnO epitaxial film grown on LaAlO3 (112) substrate
(2010-04-01)
Wang, Wei-Lin
;
Ho, Yen-Teng
;
Chiu, Kun-An
;
Peng, Chun-Yen
;
Chang, Li
The microstructure of m-plane (1 0 (1) over bar 0) ZnO grown on LaAlO3 (1 1 2) (LAO (1 1 2)) substrate by pulsed laser deposition method has been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD shows that ZnO grown on LAO(1 1 2) appears to be oriented in pure m-plane. TEM electron diffraction patterns in cross section illustrate that m-plane ZnO is in epitaxy with LAO (1 1 2), and the orientation relationships are determined to be [1 (2) over bar 1 0](ZnO)//[(1) over bar (1) over bar 1 ](LAO) and [0 0 0 1](ZnO)//[(1) over bar 1 0](LAO). Also, TEM shows that most of threading dislocations (TDs) in a-type are mainly distributed as wiggle-like lines. From the observations in plan-view TEM, the densities of TDs and basal stacking faults are approximately estimated to be 5.1 x 10(10) cm(-2) and 4.3 x 10(5) cm(-1), respectively. (C) 2009 Elsevier B.V. All rights reserved.