Microstructural Characterization of GaN Grown on SiC

2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Metal Organic

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

Deposition characteristics and microstructures of the high Tc superconducting Y1Ba2Cu3O7−δ thin films prepared by MOCVD

1991 ◽  
Vol 6 (4) ◽  
pp. 704-711 ◽  
Author(s):  
Sang Ho Kim ◽  
Chang Hyun Cho ◽  
Kwang Soo No ◽  
John S. Chun
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Zero Magnetic Field ◽  
Organic Chemical ◽  
Transmission Electron ◽  
Transformation Twins ◽  
Metal Organic ◽  
Zero Resistance ◽  
Organic Chemical Vapor Deposition

Superconducting Y1Ba2Cu3O7−δ films were prepared on the MgO (100) and SrTiO3 (100) single crystals using metal organic chemical vapor deposition (MOCVD) of β-diketone metal chelates of Y(thd)3, Ba(th)2, and Cu(thd)2. The evaporation kinetics of Y(thd)3, Ba(thd)2, and Cu(thd)2 and the ratios of deposited to evaporated mole percents of Y, Ba, and Cu cations were studied. The microstructure of Y1Ba2Cu3O7−δ films deposited using MOCVD was observed using scanning electron microscopy and transmission electron microscopy to investigate surface morphology change with the film composition and transformation twin structures. The experimental results showed that the volatility of Ba(thd)2 did not perceptively increase with decreasing evaporation pressure from 10 Torr to 5 Torr, but that of Y(thd)3 or Cu(thd)2 increased with the pressure decrease. The ratio of deposited to evaporated mole percents of Ba cation was smaller than those of Y and Cu cations. Therefore, Ba must be evaporated more than the stoichiometric amount for Y1Ba2Cu3O7−δ in order to obtain single phase Y1Ba2Cu3O7−δ films. The surface morphology of the Y1Ba2Cu3O7−δ films showed perculiar changes with slight composition changes. The transition onset and zero resistance temperatures of typical stoichiometric film deposited on MgO were 93 K and 91 K, respectively. The Y1Ba2Cu3O7−δ films had about 50 nm grain size, and most grains consisted of transformation twins. The critical current density of a film deposited on SrTiO3 was 105 A/cm2 at 77 K and zero magnetic field.

MOCVD Route to the Fabrication of Calcium Copper Titanate (CaCu3Ti4O12) Thin Films

2006 ◽  
Vol 45 ◽  
pp. 1194-1199
Author(s):  
Raffaella Lo Nigro ◽  
Roberta G. Toro ◽  
Graziella Malandrino ◽  
Ignazio L. Fragalà
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Molten Mixture ◽  
Calcium Copper Titanate ◽  
Novel Approach ◽  
Transmission Electron ◽  
Metal Organic

CaCu3Ti4O12 (CCTO) thin films have been successfully deposited by Metal Organic Chemical Vapor Deposition (MOCVD) technique. A novel approach based on a molten multicomponent precursor source has been applied. The molten mixture consists of the Ca(hfa)2•tetraglyme, Ti(tmhd)2(O-iPr)2, and Cu(tmhd)2 [Hhfa= 1,1,1,5,5,5-hexafluoro-2,4- pentanedione; tetraglyme= 2,5,8,11,14-pentaoxapentadecane; Htmhd= 2,2,6,6-tetramethyl-3,5- heptandione; O-iPr= iso-propoxide] precursors. Film complete structural and morphological characterizations have been carried out using several techniques [X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM)].

Ferroelectric Domain Boundaries Induced by Interface Mismatch Dislocations in BaTiO3/LaAlO3

1996 ◽  
Vol 466 ◽  
Author(s):  
Z. L. Wang ◽  
Z. R. Dai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Ferroelectric Domain ◽  
Organic Chemical ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

ABSTRACTInterface microstractures of BaTiO3/LaAlO3 grown by metal-organic chemical vapor deposition (MOCVD) are studied using high-resolution transmission electron microscopy (HRTEM). Interface dislocations in BaTiO3/LaAlO3 have been shown to be directly linked with the 90° domain boundaries in BaTiO3. This association is a result of strain relief due to a phase transformation on cooling from the growth temperature. The {100} surfaces of BaTiO3 are terminated with the Ba-O layer.

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

Surface Morphology of AlN Nucleation Layer Grown on Si by MOCVD

2015 ◽  
Vol 1120-1121 ◽  
pp. 391-395 ◽  
Author(s):  
Shu Fan ◽  
Le Yu ◽  
Xiao Long He ◽  
Ping Han ◽  
Cai Chuan Wu ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Growth Time ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Coverage Ratio ◽  
3 Dimensional ◽  
Aln Film ◽  
Metal Organic ◽  
Dimensional Growth ◽  
Organic Chemical Vapor Deposition

The AlN nucleation layer (NL) has been deposited on Si (111) substrate by metal-organic chemical vapor deposition (MOCVD). The result indicates that the growth mode of the AlN NL is in the form of 2-dimensional plane and 3-dimensional island. The proportion of 3-dimensional region increases gradually and the 2-dimensional region reduces correspondingly with the increase of growth time. The decrease of the coverage ratio of AlN grains in the 2-dimensional growth region is due to the effect of etching. AlN film with the single crystal orientation has been deposited on the optimized AlN NL.

Metal organic chemical vapor deposition of m-plane GaN epi-layer using a three-step approach towards enhanced surface morphology

2018 ◽  
Vol 667 ◽  
pp. 48-54
Author(s):  
Adreen Azman ◽  
Ahmad Shuhaimi ◽  
Al-Zuhairi Omar ◽  
Anas Kamarundzaman ◽  
Muhammad Imran Mustafa Abdul Khudus ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Surface Morphology ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Enhanced Surface

Characterization of Highly Textured PZT Thin Films Grown on LaNiO3 Coated Si Substrates by MOCVD

1997 ◽  
Vol 493 ◽  
Author(s):  
C. H. Lin ◽  
B. M. Yen ◽  
Haydn Chen ◽  
T. B. Wu ◽  
H. C. Kuo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Fatigue Behavior ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Preferential Orientation ◽  
Organic Chemical ◽  
Pzt Thin Films ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTHighly textured PbZrxTi1−xO3 (PZT) thin films with x= 0-0.6 were grown on LaNiO3 coated Si substrates at 600 °C by metal-organic chemical vapor deposition (MOCVD). The preferred crystalline orientation of PZT thin films with various Zr concentration were characterized by X-ray diffraction (XRD). Microstructures were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The dielectric constants, hysteresis and fatigue behavior of these thin films were also measured. The relationship between growth rate and the preferential orientation is discussed. Furthermore, the dependence of the electrical properties on Zr concentration and preferential orientation is demonstrated.

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