Influence of Mis-Orientation of C-plane Sapphire Substrate on the Early Stages of MOCVD Growth of GaN Thin Films

2004 ◽  
Vol 831 ◽  
Author(s):  
Seong-woo Kim ◽  
Hideo Aida ◽  
Toshimasa Suzuki
Keyword(s):  
Thin Films ◽  
Sapphire Substrate ◽  
Orientation Angle ◽  
Rocking Curve ◽  
Sapphire Substrates ◽  
Early Stages ◽  
Mocvd Growth ◽  
The Difference ◽  
Afm Observation

ABSTRACTWe have studied the early stages of GaN growth to realize the growth mechanism of GaN thin films on mis-oriented sapphire substrates which affects the surface and crystal quality of GaN thin films. As the result, it was found that the larger mis-orientation angle helps the growth of the larger grain of GaN and leads to the earlier shift of growth mode from 3D to 2D. The AFM observation of closed-coalesced GaN thin films revealed the difference in the micro-step structures by the mis-orientation angle of sapphire substrate. The result of x-ray rocking curve as a function of mis-orientation angle well matched with the microstructure of GaN surface, indicating that the larger mis-orientation angle helps the column ordering of GaN crystals.

Growth of ZnO Thin Films on Sapphire Substrates by ECR-Assisted MBE

1997 ◽  
Vol 474 ◽  
Author(s):  
Hee-Bog Kang ◽  
Kiyoshi Nakamura ◽  
Kazuo Ishikawa
Keyword(s):  
Sapphire Substrate ◽  
Electron Cyclotron Resonance ◽  
Rf Sputtering ◽  
Zno Films ◽  
Zno Film ◽  
Epitaxial Relationship ◽  
Rocking Curve ◽  
Sapphire Substrates ◽  
Relationship Of ◽  
Ecr Source

ABSTRACTEpitaxial ZnO films were grown on c-plane sapphire substrate at low temperature using the electron cyclotron resonance-assisted molecular beam epitaxy(ECR-assisted MBE) technique. In this method, Zn vapor provided by a Knudsen cell reacts with oxygen activated in an ECR source on the surface of sapphire substrate. The crystal structure, surface morphology and epitaxial relationship of the films were investigated. It was confirmed that the ECR-assisted MBE technique was capable of growing a high quality epitaxial ZnO films on c-plane sapphire substrates at low temperatures in comparison with CVD and RF sputtering. The FWHM of an x-ray rocking curve of the (0002) peak for a 0.33μ-thick ZnO film was as narrow as 0.58°. The epitaxial relationship between ZnO film and c-plane sapphire substrate was determined to be (0001)ZnO//(0001)Al2O3 with in-plane alignment of [1100]ZnO//[2110]Al2O3, which is equivalent to the 30° rotation of ZnO relative to sapphire in the c-plane.

scholarly journals Surface morphology and X-ray photoelectron spectroscopy of BiFeO3 thin films deposited on top of Ta2O5/Si layers

2021 ◽  
Vol 295 ◽  
pp. 04009
Author(s):  
Shikhgasan Ramazanov ◽  
Ştefan Ţălu ◽  
Rashid Dallaev ◽  
Guseyn Ramazanov ◽  
Pavel Škarvada ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Bismuth Ferrite ◽  
Ferrite Film ◽  
Bifeo3 Thin Films ◽  
Expansion Coefficients ◽  
The Difference ◽  
First Time ◽  
The Relationship

In this study a comparison of the topography of BiFeO3 (BFO) thin films deposited on tantalum pentoxide substrates of different thicknesses is provided. The Ta2O5 substrates had a roughness increasing with the film thickness. The relationship between substrates of different topography but the same composition with the quality of the growing bismuth ferrite film is estimated. For the first time the topography estimation of BFO on Ta2O5 is presented. The difference in temperature expansion coefficients leads to intensive evaporation of bismuth ferrite from the surface during annealing. XPS analysis is provided for asdeposited and annealed BFO layers.

Grinding Performance Evaluation of the Developed Chemo-Mechanical Grinding (CMG) Tools for Sapphire Substrate

2012 ◽  
Vol 565 ◽  
pp. 105-110 ◽  
Author(s):  
Zhi Gang Dong ◽  
Shang Gao ◽  
P. Zhou ◽  
Ren Ke Kang ◽  
Dong Ming Guo
Keyword(s):  
Surface Roughness ◽  
Performance Evaluation ◽  
Surface Quality ◽  
Sapphire Substrate ◽  
Physicochemical Characteristics ◽  
Diamond Wheel ◽  
Mechanical Grinding ◽  
Sapphire Substrates ◽  
Grinding Performance

In order to improve the surface quality of sapphire substrates ground by diamond wheel, the chemo-mechanical grinding (CMG) tools for sapphire grinding was investigated in this paper. According to the processing principle of CMG, three CMG tools with different abrasives of SiO2, Fe2O3 and MgO were developed respectively. The compositions of the CMG tools were designed and optimized based on the physicochemical characteristics of sapphire. The grinding experiments were performed with the developed CMG tools and the grinding performance of three kind of tools were evaluated by comparing the surface roughness and the MRR of sapphire. The experiment results show that the grinding performance of SiO2 CMG tool was worst. The surface roughness and MRR corresponding to SiO2 CMG tool were all significantly poorer than Fe2O3 and MgO CMG tools. The highest MRR could be obtained by Fe2O3 CMG tool, but the best surface quality was obtained by MgO CMG tool.

Schottky I-V Characteristics of Au/Ni/GaN/SiNx nanonework/sapphire structures

2006 ◽  
Vol 955 ◽  
Author(s):  
Jinqiao Xie ◽  
Yi Fu ◽  
Hadis Morkoç
Keyword(s):  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Schottky Diodes ◽  
Chemical Vapor ◽  
Rocking Curve ◽  
X Ray ◽  
Sapphire Substrates ◽  
Control Samples

ABSTRACTGaN layers on sapphire substrates were grown by metalorganic chemical vapor deposition using in situ porous SiNx nano-network. Crystalline quality of epilayers was characterized by X-ray rocking curve scans, and the full width at hall maximum values for (002) and (102) diffractions were improved from 252 arc sec and 405 arc sec, respectively, in control samples to 216 arc sec and 196 arc sec when SiNx was used. Ni/Au Schottky diodes (SDs) were fabricated and the SD performance was found to be critically dependent on the SiNx coverage (fewer and farther the pores the better the results) which is consistent with the trends of XRD and photoluminescence data. A 1.13eV barrier height was achieved when 5min SiNx layer was used compared with 0.78 eV without any SiNx nanonetwork. Furthermore, the breakdown voltage improved from 76 V to 250V when SiNx nanonetwork was used in otherwise identical structures.

Determination of domain structure and abundance of epitaxial Pb(Zr, Ti)O3 thin films grown on MgO(001) by rf magnetron sputtering

1999 ◽  
Vol 14 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Kyeong Seok Lee ◽  
Young Min Kang ◽  
Sunggi Baik
Keyword(s):  
Thin Films ◽  
Curie Temperature ◽  
Magnetron Sputtering ◽  
Domain Structure ◽  
Rf Magnetron Sputtering ◽  
Curve Analysis ◽  
Crystalline Quality ◽  
Rocking Curve ◽  
X Ray

Epitaxial Pb(ZrxTi1−x)O3 (x = 0.0−0.32) ferroelectric thin films of 500 nm thickness were grown on MgO(001) single crystal substrates by in situ rf magnetron sputtering, and evolution of their domain structures is characterized by employing various x-ray diffraction techniques. X-ray θ-2θ scan showed the films were grown highly c-axis oriented with a tetragonal perovskite structure. 90° domain configuration was investigated using the x-ray rocking curve analysis for PZT 100 peaks in two different Φphi; angles. The rocking curve analysis showed that the degree of c-axis orientation and the crystalline quality of the films were improved continuously with increasing Zr concentration. The c-domain abundance as a function of Zr concentration was quantified using the x-ray rocking curves of PZT 001 and 100, taking account of structural factors and Lorentz-polarization factors. High temperature x-ray technique was also employed to quantify the domain structure as a function of temperature during cooling after reheating the samples to 650 °C. During the cooling process, c-domain abundance was found to increase continuously while the crystalline quality of the films was deteriorated below the Curie temperature. The results led us to conclude that the transformation strain of the film at and below the Curie temperature plays a significant role in the final domain structure and abundance of epitaxial PZT thin films.

Ferroelectric domain structure of epitaxial (Pb,Sr)TiO3 thin films

2001 ◽  
Vol 16 (9) ◽  
pp. 2463-2466 ◽  
Author(s):  
Yong Kwan Kim ◽  
Kyeong Seok Lee ◽  
Sunggi Baik
Keyword(s):  
Thin Films ◽  
Curie Temperature ◽  
Transformation Strain ◽  
Systematic Change ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Rocking Curve ◽  
Lattice Constants ◽  
Ferroelectric Domain Structure

Epitaxial (Pb1−xSrx)TiO3 (PST, x = 4 0.0–0.24) thin films were grown on MgO(001) single-crystal substrates by pulsed laser deposition. General x-ray diffraction techniques including θ–2θ scan and rocking curve were used to determine lattice constants, degree of c-axis orientation, and crystal quality of the tetragonal thin films. The degree of c-axis orientation in the epitaxial PST films increased as Sr concentration (x) increased, which in turn induces the systematic change in the Curie temperature as well as the transformation strain at and below the Curie temperature. An inverse relation between the c-domain abundances and the transformation strains is established.

Research on the Properties of NiZnO Thin Films

2011 ◽  
Vol 130-134 ◽  
pp. 1491-1494
Author(s):  
Xin Dong ◽  
Jin Wang ◽  
Hui Wang ◽  
Zhi Feng Shi ◽  
Long Zhao
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Electrical Properties ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Crystal Structure Analysis ◽  
Organic Chemical ◽  
Sapphire Substrates ◽  
Metal Organic

NiZnO thin films had been fabricated on c-plane sapphire substrates using photo-assisted metal organic chemical vapour deposition system. The crystal quality of the films had been improved greatly comparing to the results in earlier reports. The crystal structure analysis indicated the NiZnO kept the basic wurtzite structure until the content of Ni attained 0.18. The crystal and electrical properties of the films showed the content of Ni had an important effect on the properties of NiZnO films.

Crystalline anisotropy of β-Ga2O3 thin films on c-plane GaN template and sapphire substrate

2021 ◽  
Author(s):  
Xiaocui Ma ◽  
Rui Xu ◽  
Yang Mei ◽  
Leiying Ying ◽  
Hao Long ◽  
...  
Keyword(s):  
Thin Films ◽  
Sapphire Substrate ◽  
Lattice Mismatch ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallographic Anisotropy ◽  
Crystalline Anisotropy

Abstract In this work, crystalline anisotropy of heteroepitaxial (-201) β-Ga2O3 films on c-plane sapphire substrate and GaN template was investigated by X-ray diffraction. The (-201) ω-scan broadening of β-Ga2O3 on GaN exhibited six-fold rotational symmetric anisotropy along different azimuths, with maxima along [010] and minima along [102] direction, respectively. However, in case of β-Ga2O3 on sapphire, it was nearly isotropic. Smaller lattice mismatch between β-Ga2O3 and GaN were taken into account to explain the discrepancy, which also explained the better quality of β-Ga2O3 deposited on GaN. Our results presented a new viewpoint to the crystallographic anisotropy of (-201 ) β-Ga2O3 thin films.

Chemical vapor deposition of diamond on an adamantane-coated sapphire substrate

RSC Advances ◽  
2014 ◽  
Vol 4 (36) ◽  
pp. 18945-18950 ◽  
Author(s):  
Yi-Chun Chen ◽  
Li Chang
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Sapphire Substrate ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Dip Coating ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Sapphire Substrates

Continuous diamond thin films can be grown on sapphire substrates by microwave plasma chemical vapor deposition utilizing a pretreatment of adamantane dip coating on the substrate for enhanced nucleation.

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