The evolution of a GaN/sapphire interface with different nucleation layer thickness during two-step growth and its influence on the bulk GaN crystal quality

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 51201-51207 ◽  
Author(s):  
Lin Shang ◽  
Taiping Lu ◽  
Guangmei Zhai ◽  
Zhigang Jia ◽  
Hua Zhang ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Chemical Vapor ◽  
Crystal Quality ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Bulk Gan ◽  
Metal Organic ◽  
Step Growth ◽  
Gan Crystal

The role of the nucleation layer thickness on the GaN crystal quality grown by metal organic chemical vapor deposition is explored.

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.

Grain-Size-Dependent Thermal Transport Properties in Nanocrystalline Yttria-Stabilized Zirconia

2001 ◽  
Vol 703 ◽  
Author(s):  
Ho-Soon Yang ◽  
J.A. Eastman ◽  
L.J. Thompson ◽  
G.-R. Bai
Keyword(s):  
Grain Boundaries ◽  
Thermal Transport ◽  
Chemical Vapor ◽  
Yttria Stabilized Zirconia ◽  
Organic Chemical ◽  
Stabilized Zirconia ◽  
Size Dependent ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

ABSTRACTUnderstanding the role of grain boundaries in controlling heat flow is critical to the success of many envisioned applications of nanocrystalline materials. This study focuses on the effect of grain boundaries on thermal transport behavior in nanocrystalline yttria-stabilized zirconia (YSZ) coatings prepared by metal-organic chemical vapor deposition.

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.

Phase Control of Ga2O3 Thin Films Grown by Metal-Organic Chemical Vapor Deposition

2019 ◽  
Vol 954 ◽  
pp. 72-76
Author(s):  
Ze Qi Li ◽  
Zi Min Chen ◽  
Wei Qu Chen ◽  
Gang Wang
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Flow Rates ◽  
Growth Method ◽  
Metal Organic ◽  
Step Growth ◽  
Organic Chemical Vapor Deposition

In this paper, Ga2O3 thin films were grown on c-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD). There was phase transition for samples grown with different flow rates of triethyl-gallium (TEGa) and deionized water (H2O). It is found that ε-Ga2O3 is difficult to coalesce and the phase mixture by β­Ga2O3 takes place if the flow rates of TEGa and H2O are too high. However, by using multiple-step growth method, the film became fully coalesced. High-quality ε-Ga2O3 thin film with atomically flat surface and multilayer morphology was obtained.

scholarly journals Investigation of AlGaN/GaN Heterostructures Grown on Sputtered AlN Templates with Different Nucleation Layers

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4050 ◽  
Author(s):  
Chuan-Yang Liu ◽  
Ya-Chao Zhang ◽  
Sheng-Rui Xu ◽  
Li Jiang ◽  
Jin-Cheng Zhang ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Layer Growth ◽  
Organic Chemical ◽  
Propagation Mechanism ◽  
Nucleation Layer ◽  
Low Dislocation Density ◽  
Structural And Electrical Properties ◽  
Metal Organic

In this work, a sputtered AlN template is employed to grow high-quality AlGaN/GaN heterostructures, and the effects of AlN nucleation layer growth conditions on the structural and electrical properties of heterostructures are investigated in detail. The optimal growth condition is obtained with composited AlN nucleation layers grown on a sputtered AlN template, resulting in the smooth surface morphology and superior transport properties of the heterostructures. Moreover, high crystal quality GaN material with low dislocation density has been achieved under the optimal condition. The dislocation propagation mechanism, stress relief effect in the GaN grown on sputtered AlN, and metal organic chemical vapor deposition AlN nucleation layers are revealed based on the test results. The results in this work demonstrate the great potential of AlGaN/GaN heterostructures grown on sputtered AlN and composited AlN nucleation layers for microelectronic applications.

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