Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition

2019 ◽  
Vol 52 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Jiang-Dong Gao ◽  
Jian-Li Zhang ◽  
Xin Zhu ◽  
Xiao-Ming Wu ◽  
Chun-Lan Mo ◽  
...  

The growth mechanism of V-defects in GaN films was investigated. It was observed that the crystal faces of both the sidewall of a V-defect and the sidewall of the GaN film boundary belong to the same plane family of \{ {{{10\bar 11}}} \}, which suggests that the formation of the V-defect is a direct consequence of spontaneous growth like that of the boundary facet. However, the growth rate of the V-defect sidewall is much faster than that of the boundary facet when the V-defect is filling up, implying that lateral growth of \{ {{{10\bar 11}}} \} planes is not the direct cause of the change in size of V-defects. Since V-defects originate from dislocations, an idea was proposed to correlate the growth of V-defects with the presence of dislocations. Specifically, the change in size of the V-defect is determined by the growth rate around dislocations and the growth rate around dislocations is determined by the growth conditions.

1991 ◽  
Vol 238 ◽  
Author(s):  
David N. Jamieson ◽  
S. P. Dooley ◽  
S. P. Russo ◽  
P. N. Johnston ◽  
G. N. Pain ◽  
...  

ABSTRACTHg1-xCdxTe epitaxial layers on GaAs substrates grown by Metal Organic Chemical Vapour Deposition (MOCVD) display growth defects resembling pyramidal faceted hillocks which appear to originate from defects originally present on the substrate. For <100> oriented GaAs substrates and normal growth conditions, these growth defects have an areal density of 1–1000 mm-2. The size of the hillocks depends on the layer thickness and they have the potential to degrade performance of optoelectronic devices fabricated in the epitaxial layers. Nuclear microprobe analysis, performed with a 2 MeV He+ beam focused to less than 5 μm in diameter, has allowed the hillocks to be imaged with the technique of Channeling Contrast Microscopy (CCM). Channeling spectra, obtained by Rutherford Backseat tering Spectrometry (RBS) of the hillocks themselves, showed that the χmin was 13 %. This was similar to the χmin of the high quality single crystal surrounding material. The CCM images also revealed extensive regions of poor channeling, with shapes that suggested that the regions originally arose from scratches in the substrate. These poor channeling regions were not readily observable by other techniques.


2006 ◽  
Vol 957 ◽  
Author(s):  
Soo Jin Chua ◽  
Hai Long Zhou ◽  
Hui PAN ◽  
Thomas Osipowicz

ABSTRACTZnO is grown by chemical vapour deposition on {1 1 -2 2} GaN planes formed by epitaxial layer overgrowth. Window stripes in a SiO2 mask are oriented in the <1 -1 0 0> direction of the GaN film. Triangular GaN ridge are formed during ELO growth by metal organic chemical vapour deposition. A flat (0 0 0 1) ZnO plane is grown on each triangular cross-section ridge and it is found that the ZnO film has dislocation density reduced by two orders of magnitude compared to that of the GaN substrate.


1990 ◽  
Vol 200 ◽  
Author(s):  
F.W. Ainger ◽  
C.J. Brierley ◽  
M.D. Hudson ◽  
C. Trundle ◽  
R.W. Whatmore

ABSTRACTThere is a growing interest in thin films of ferroelectric oxides because of their electronic and optoelectronic applications. Various growth processes are being explored, but here, we review progress with chemical vapour deposition in a purpose built low pressure reactor. The two ferroelectric perovskites selected for our initial studies were lead titanate and lead scandium tantalate which have necessitated the synthesis of proprietary precursors. These compounds are based on metal alkoxides and β-diketonates, and are suitably modified to exhibit the required volatility and necessary thermal and hydrolytic stabilities.Deposition has been studied over the temperature range 400–800°C and, in general, amorphous films result which can be converted by subsequent annealing to crystalline perovskites. However, the inclusion of hydroxyl group compounds (H2O or alcohols) in the vapour train catalyses the crystallisation process and enhances the growth rates at temperatures in excess of 600°C. In order to deposit the perovskite phase, it is important to maintain the gas phase composition throughout the growth. Deposition rates of up to 10μm/hour can be achieved, but the best thin films, in terms of density and morphology, are formed at lower deposition rates. The crystallite size of the deposit may vary from 0.1μm up to 2μm, depending on temperature. The choice of precursors, gas compositions and the growth conditions will be discussed in conjunction with the electrical and structural properties of the layers grown.


2013 ◽  
Vol 113 (14) ◽  
pp. 143513 ◽  
Author(s):  
D. N. Montenegro ◽  
V. Hortelano ◽  
O. Martínez ◽  
M. C. Martínez-Tomas ◽  
V. Sallet ◽  
...  

2020 ◽  
Vol 53 (1) ◽  
pp. 302-302
Author(s):  
Jiang-Dong Gao ◽  
Jian-Li Zhang ◽  
Xin Zhu ◽  
Xiao-Ming Wu ◽  
Chun-Lan Mo ◽  
...  

An error in the article by Gao, Zhang, Zhu, Wu, Mo, Pan, Liu & Jiang [J. Appl. Cryst. (2019), 52, 637–642] is corrected.


Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).


Author(s):  
L. Solymar ◽  
D. Walsh ◽  
R. R. A. Syms

Both intrinsic and extrinsic semiconductors are discussed in terms of their band structure. The acceptor and donor energy levels are introduced. Scattering is discussed, from which the conductivity of semiconductors is derived. Some mathematical relations between electron and hole densities are derived. The mobilities of III–V and II–VI compounds and their dependence on impurity concentrations are discussed. Band structures of real and idealized semiconductors are contrasted. Measurements of semiconductor properties are reviewed. Various possibilities for optical excitation of electrons are discussed. The technology of crystal growth and purification are reviewed, in particular, molecular beam epitaxy and metal-organic chemical vapour deposition.


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