Complex Flow and Gas-Phase Reactions in a Horizontal Reactor  for GaN Metalorganic Vapor Phase Epitaxy

Harafuji, Kenji; Hasegawa, Yoshihiko; Ishibashi, Akihiro; Tsujimura, Ayumu; Kidoguchi, Isao; Ban, Yuzaburoh; Ohnaka, Kiyoshi

doi:10.1143/jjap.39.6180

Cited by 12 publications

(10 citation statements)

References 14 publications

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“…Several pertinent papers have been published which analyse the flow dynamics and the gas phase chemistry [152][153][154]. However, gas-surface reactions were oversimplified.…”

Section: Theoretical Analysis Of Elomentioning

confidence: 99%

Epitaxial Lateral Overgrowth of GaN

Beaumont

Vennéguès

Gibart

2001

phys. stat. sol. (b)

191

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Since there is no GaN bulk single crystal available, the whole technological development of GaN based devices relies on heteroepitaxy. Numerous defects are generated in the heteroepitaxy of GaN on sapphire or 6H‐SiC, mainly threading dislocations (TDs). Three types of TDs are currently observed, a type (with Burgers vector 1/3〈$11 \bar{2}0$〉); c type (with 〈0001〉) and mixed a+c (1/3〈$11 \bar{2}3$〉). The Epitaxial Lateral Overgrowth (ELO) technology produces high quality GaN with TD densities in the mid 106 cm—2, linewidth of the low‐temperature photoluminescence (PL) near‐bandgap recombination peaks <1 meV and deep electron traps reduced below 1014 cm—3 (compared to mid 1015 cm—3 in standard GaN). Numerous modifications of the ELO process have been proposed in order either to avoid technological steps (mask‐less ELO) or to improve it (pendeo‐epitaxy). Basically developed on either sapphire or 6H‐SiC, the ELO technology is also achievable on (111)Si or (111)3C‐SiC/Si provided that an appropriate buffer layer is grown to avoid cracks. More sophisticated technologies have been implemented to further increase the useable part of the ELO GaN surface (two technological steps, three‐step ELO). Unfortunately, in‐depth understanding of the basic ELO process is still missing, i.e. of the growth anisotropy and bending of dislocations.

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“…Several pertinent papers have been published which analyse the flow dynamics and the gas phase chemistry [152][153][154]. However, gas-surface reactions were oversimplified.…”

Section: Theoretical Analysis Of Elomentioning

confidence: 99%

Epitaxial Lateral Overgrowth of GaN

Beaumont

Vennéguès

Gibart

2001

phys. stat. sol. (b)

191

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“…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: 91%

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

Ohkawa

Hirako

Yoshitani

2001

phys. stat. sol. (a)

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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.

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“…Constant temperatures 1300 K and 310 K are given across the susceptor surface and on the cold wall, respectively. Transport properties of viscosity, thermal conductivity and diffusion coefficient for the gas mixture are modeled as a function of the local values of temperature and mole fraction [3,4].…”

Section: Simulation Modelmentioning

confidence: 99%

Gas-Phase and Surface Reactions in a Horizontal Reactor for GaN MOVPE Growth

Harafuji

2001

phys. stat. sol. (a)

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Three-dimensional simulations of gas flow and chemical reactions are made. The epitaxy model is newly developed. It is found that the gas flow rate Q is a key parameter which controls the spatial distribution of the growth rate above the susceptor. Here, Q is proportional to pressure and flow velocity. At low Q, the peak position of the growth rate shifts in the upstream direction. At an optimum Q, the growth rate distribution is spatially uniform. At high Q, the distribution is a split one with respect to the reactor symmetry plane. This is due to the peaking of gas flow velocity around the symmetry plane, which is driven by a pair of large return-flows around tapered gas entrance region.Introduction Gallium nitride (GaN) has been confirmed as a key material for achieving violet laser diodes (LDs) through recent splendid development [1,2]. Metalorganic vapor phase epitaxy (MOVPE) is a leading technology for this purpose. This technology is, however, not a satisfactory level for high power commercial LDs from the standpoint of crystal quality itself and the overall epitaxy process control. Numerical calculation is one of the powerful tools for analyzing the physical and chemical mechanism and finding the pathway to an optimal process condition. In this paper, three-dimensional simulations of gas flow and chemical reactions are made in a horizontal reactor for GaN MOVPE. Attention is paid to the effect of the gas flow velocity and gas pressure on the spatial distribution of both streamlines and the surface reaction rate.

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Complex Flow and Gas-Phase Reactions in a Horizontal Reactor for GaN Metalorganic Vapor Phase Epitaxy

Cited by 12 publications

References 14 publications

Epitaxial Lateral Overgrowth of GaN

Epitaxial Lateral Overgrowth of GaN

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

Gas-Phase and Surface Reactions in a Horizontal Reactor for GaN MOVPE Growth

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