The importance of predicting rate-limited growth for accurate modeling of commercial MOCVD reactors

Phys. Status Solidi (c)

Ohkawa

2010

We report computational analysis of gas‐phase states and main reaction pathways under AlN metalorganic vapor‐phase epitaxy (MOVPE) by pulsed injection (PI) method of precursors. Interval times of 0–2 s were inserted between trimethylaluminum (Al(CH3); TMAl) and ammonia (NH3) supply phases to suppress parasitic reactions. In the cases of the interval time of 0 s, polymers and Al‐N molecules were dominant species due to parasitic reaction, and the growth species was Al‐N molecules generated by TMAl:NH3 pyrolysis. When an interval time was inserted between TMAl and NH3, mixing of TMAl and NH3 were suppressed. Al and NH2 generated from each precursor were dominant species. The main reaction pathway changed from TMAl:NH3 pyrolysis into TMAl pyrolysis with increasing the interval time. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Section: Modeling and Simulationmentioning

confidence: 99%

Analysis of pulsed injection of precursors in AlN‐MOVPE growth by computational fluid simulation

Nakamura¹,

Phys. Status Solidi (c)

Ohkawa

2010

“…In the CFD simulation, steady-state solutions were derived by using the commercial code CFD-ACE+, in which basic fluid equations of mass, momentum and energy conservation laws, as well as chemical reactions were solved by means of finite volume method [4][5][6][7]. A two-dimensional horizontal reactor was employed, in this study, because a main issue was to obtain general insight of the chemical state in vapor phase and surface site.…”

Section: Cfd Simulationmentioning

confidence: 99%

“…For the gaseous chemistry in MOVPE-GaAs, the themal decomposition of group-III precursor without parasitic reactions, such as from TMG to dimethylgallium (DMG), DMG to monomethylgallium (MMG) and MMG to Ga-atom, are occurred [7]. It is pointed out, however, that parasitic reactions are appeared in MOVPE-GaN growth.…”

Section: Cfd Simulationmentioning

confidence: 99%

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Computational fluid dynamics on gaseous and surface chemistry of GaN‐MOVPE system for various pressures

Kusakabe

Tanaka

et al. 2004

phys. stat. sol. (c)

Pressure effects on gaseous and surface chemistry of GaN grown by metalorganic vapor phase epitaxy (MOVPE) were studied. In order to obtain a chemical state of molecular species in an MOVPE reactor, computational fluid dynamics simulation was performed for 10 to 300 kPa, in which parasitic reactions among trimethylgallium and ammonia were considered. It was found that adducts of the dimethylgallium-NH 2 family related to Ga-N molecule formation dominated reaction pathways. It was also revealed that a V/III ratio of physisorbed species was increased 2 orders of magnitude and close to a unity with the reactor pressure. These results suggested that MOVPE growth under atmospheric or higher pressures resulted in favourable growth conditions for high quality GaN.

“…CFD simulation is powerful to visualize gas flow. The recent CFD code has shown good agreement among its simulation and experiment of MOVPE growth of GaAs [2]. It is possible to see not only gas flow and temperature but also chemical species concentration if chemical reactions are considered [3].…”

Section: Introductionmentioning

confidence: 90%

Growth of GaN Layers by One-, Two-, and Three-Flow Metalorganic Vapor Phase Epitaxy

Ohkawa

Yoshitani

2001

phys. stat. sol. (a)

Subject classification: 73.61.Ey; 81.15.Kk; S7.14 One-, two-and three-flow metalorganic vapor phase epitaxy (MOVPE) methods have been compared in GaN growth, and each growth is analyzed by computational fluid dynamics (CFD). It is found that two-flow method shows better growth condition for achieving high quality layers compared to one-and three-flow methods. A GaN layer with high Hall mobility of 360 cm 2 /Vs is obtained by two-flow MOVPE growth despite no low-temperature buffer layer. The V/III decomposition ratio of NH 2 /GaCH 3 is calculated by CFD simulation in gas phase just on substrate surface. The V/III ratio is in a narrow region to get high-mobility samples.