The Effect of Carrier Gas and Reactor Pressure on Gallium Nitride Growth in MOCVD Manufacturing Process

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Omar Jumaah ◽  
Yogesh Jaluria

Gallium nitride (GaN) is an attractive material for manufacturing light emitting diodes and other electronic devices due to its wide band-gap and superb optoelectronic performance. The quality of GaN thin film determines the reliability and durability of these devices. Metal-organic chemical vapor deposition (MOCVD) is a common technique used to fabricate high-quality GaN thin films. In this paper, GaN growth rate and uniformity in a vertical rotating disk MOCVD reactor are investigated on the basis of a three-dimensional computational fluid dynamics (CFD) model. GaN growth rate is investigated under the influence of reactor pressure, precursor concentration ratio, and composition of the carrier gas mixture. The numerical simulation shows that the carrier gas mixture and the reactor pressure have significant effects on growth rate and uniformity of GaN thin films. It is also found that an appropriate mixture of N2 and H2 may be employed as the carrier gas to improve the flow field characteristic in the reactor. This results in an improved crystal growth of GaN thin films.

2021 ◽  
Author(s):  
Omar D. Jumaah ◽  
Yogesh Jaluria

Abstract Chemical vapor deposition (CVD) is a widely used manufacturing process for obtaining thin films of materials like silicon, silicon carbide, graphene and gallium nitride that are employed in the fabrication of electronic and optical devices. Gallium nitride (GaN) thin films are attractive materials for manufacturing optoelectronic device applications due to their wide band gap and superb optoelectronic performance. The reliability and durability of the devices depend on the quality of the thin films. The metal-organic chemical vapor deposition (MOCVD) process is a common technique used to fabricate high-quality GaN thin films. The deposition rate and uniformity of thin films are determined by the thermal transport processes and chemical reactions occurring in the reactor, and are manipulated by controlling the operating conditions and the reactor geometrical configuration. In this study, the epitaxial growth of GaN thin films on sapphire (AL2O3) substrates is carried out in two commercial MOCVD systems. This paper focuses on the composition of the precursor and the carrier gases, since earlier studies have shown the importance of precursor composition. The results show that the flow rate of trimethylgallium (TMG), which is the main ingredient in the process, has a significant effect on the deposition rate and uniformity of the films. Also the carrier gas plays an important role in deposition rate and uniformity. Thus, the use of an appropriate mixture of hydrogen and nitrogen as the carrier gas can improve the deposition rate and quality of GaN thin films.


2014 ◽  
Vol 563 ◽  
pp. 50-55 ◽  
Author(s):  
Raffaella Lo Nigro ◽  
Sergio Battiato ◽  
Giuseppe Greco ◽  
Patrick Fiorenza ◽  
Fabrizio Roccaforte ◽  
...  

2013 ◽  
Vol 275-277 ◽  
pp. 2023-2026 ◽  
Author(s):  
Ai Hua Jiang ◽  
Hao Yu Jiang ◽  
Hang Zhao ◽  
Jian Rong Xiao

Gallium nitride (GaN) thin films samples were grown by metal-organic chemical vapor deposition (MOCVD) with ammonia and trimethyl-gallium, and the samples were annealed rapidly at different temperature. The scanning electron microscope (SEM) analysis was employed to study the surface morphology and lattice defects of the GaN thin films. The surface morphology of the thin films prepared at different condition was uniform and smoothly. The relationship of the films defects and the annealed temperature were summarized.


Author(s):  
Jiandong Meng ◽  
Yogesh Jaluria

A numerical study has been carried out to characterize the metalorganic chemical vapor deposition (MOCVD) growth of Gallium Nitride (GaN) in a rotating-disk reactor. The major objective of this work is to examine the dependence of the growth rate and thin film uniformity on the primary parameters. First of all, for a rotating-disk system, the governing equations involved are obtained. Then, with the effect of thermal buoyancy included and based on the detailed mathematical model and chemical reaction mechanisms, the 3D simulation study is conducted for a rotating reactor. A comparison between the predicted growth rate and experimental data is presented. In addition, the effect of various primary operating and design parameters on the growth rate of GaN and thin-film uniformity is also examined. This provides further insight into the reactor performance and the characteristics of the entire process. The results obtained can also form the basis for the future design and optimization of this system.


2011 ◽  
Vol 25 (31) ◽  
pp. 4171-4174 ◽  
Author(s):  
Toshihide Horikawa ◽  
Hiroyuki Asano ◽  
Kazuhide Akiyama ◽  
Daisuke Nakahara ◽  
Masahiro Katoh

Titanium dioxide ( TiO 2) thin films are prepared on glass substrates by metal-organic chemical vapor deposition (MOCVD) method using the different organic solvents, e.g. ethanol or cyclohexane, in nitrogen carrier gas with different their concentrations. We reported the effects of the each organic solvent in the carrier gas for MOCVD method on the morphology of the composed particles, the thickness, the surface roughness, and the transparency of the prepared TiO 2 thin films with changing the deposition temperature. The morphology of the particles which compose the thin films, and the surface roughness of the prepared TiO 2 thin films are observed and measured by atomic force microscope (AFM) and field emission scanning electron microscopy (FE-SEM). The film thickness is measured by fluorescent X-ray spectroscopy (XRF), and the transparency of the films is confirmed by UV-vis spectroscopy. The transparencies of the TiO 2 thin films differ depending on the MOCVD conditions, e.g. the organic solvents species, the concentration of the container in the carrier gas and the deposition temperatures. We have found that the species and the concentration of the organic solvents in the carrier gas are very important factor to prepare homogeneous TiO 2 thin films by MOCVD method; cyclohexane inhibits to aggregate of the TiO 2 nanoparticles on the glass substrate during the MOCVD process.


Author(s):  
Jason R. Heffelfinger ◽  
C. Barry Carter

Yttria-stabilized zirconia (YSZ) is currently used in a variety of applications including oxygen sensors, fuel cells, coatings for semiconductor lasers, and buffer layers for high-temperature superconducting films. Thin films of YSZ have been grown by metal-organic chemical vapor deposition, electrochemical vapor deposition, pulse-laser deposition (PLD), electron-beam evaporation, and sputtering. In this investigation, PLD was used to grow thin films of YSZ on (100) MgO substrates. This system proves to be an interesting example of relationships between interfaces and extrinsic dislocations in thin films of YSZ.In this experiment, a freshly cleaved (100) MgO substrate surface was prepared for deposition by cleaving a lmm-thick slice from a single-crystal MgO cube. The YSZ target material which contained 10mol% yttria was prepared from powders and sintered to 85% of theoretical density. The laser system used for the depositions was a Lambda Physik 210i excimer laser operating with KrF (λ=248nm, 1Hz repetition rate, average energy per pulse of 100mJ).


2021 ◽  
Vol 15 (6) ◽  
pp. 2170024
Author(s):  
Yuxuan Zhang ◽  
Zhaoying Chen ◽  
Kaitian Zhang ◽  
Zixuan Feng ◽  
Hongping Zhao

1995 ◽  
Vol 388 ◽  
Author(s):  
Rand R. Biggers. ◽  
M. Grant Norton ◽  
I. Maartense ◽  
T.L. Peterson ◽  
E. K. Moser ◽  
...  

AbstractThe pulsed-laser deposition (PLD) technique utilizes one of the most energetic beams available to form thin films of the superconducting oxide YBa2Cu3O7 (YBCO). IN this study we examine the growth of YBCO at very high laser fluences (25 to 40 J/cm2); a more typical fluence for PLD would be nearer to 3 J/cm2. the use of high fluences leads to unique film microstructures which, in some cases, appear to be related to the correspondingly higher moveabilities of the adatoms. Films grown on vicinal substrates, using high laser fluences, exhibited well-defined elongated granular morphologies (with excellent transition temperature, Tc, and critical current density, Jc). Films grown on vicinal substrates using off-axis magnetron sputtering, plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD), or PLD at more typical laser fluences showed some similar morphologies, but less well-defined. Under certain growth conditions, using high laser fluences with (001) oriented substrates, the YBCO films can exhibit a mixture of a- and c-axis growth where both crystallographic orientations nucleate on the substrate surface at the same time, and grow in concert. the ratio of a-axis oriented to c-axis oriented grains is strongly affected by the pulse repetition rate of the laser.


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