Plasma-assisted electroepitaxy of GaN layers from the liquid Ga melt

Новиков, С. В.; Foxon, C.T.

doi:10.1016/j.jcrysgro.2012.05.040

Cited by 10 publications

(11 citation statements)

References 16 publications

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“…The growth rate of the of the film was ∼0.5 μm/h, which is similar to growth rates obtained in MOCVD processes. However, this growth rate is significantly faster than the growth rate obtained by Novikov et al during their plasma-assisted electroepitaxy process …”

Section: Resultsmentioning

confidence: 55%

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Liquid Phase Epitaxy of Gallium Nitride

Jaramillo-Cabanzo

Jasiński

Sunkara

2019

Crystal Growth & Design

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In this work, liquid phase epitaxy of gallium nitride (GaN) has been achieved using pulsed plasma nitridation of molten Ga films. Typically, continuous exposure of Ga to nitrogen plasma results in the formation of a thick GaN crust that prevents the growth of GaN layers on GaN seeds or GaN-on-sapphire substrates. The GaN crust formation on molten Ga is a consequence of a high concentration of dissolved nitrogen at the top surface of molten Ga layers. Here, we present the concept of using pulse (on/off) sequences to control the concentration of nitrogen inside the melt and enable the growth of GaN at the molten Ga−substrate interface. Results showed that the technique allows for epitaxial growth on homosubstrates and promotes the growth of additional layers on the pre-existing seeds. High-resolution transmission electron microscopy characterization confirmed epitaxial growth of GaN. A mass transport model was developed to discuss the effect of bulk recombination, diffusion, and pulsing on the concentration of nitrogen into the molten Ga. Results indicated that pulsing favored both the recombination of radicals in the bulk and the diffusion of species into the metal compared to the dissolution of radicals. As a result, the concentration of nitrogen at the surface of the metal is decreased, while the concentration of nitrogen at the molten Ga−substrate interface is increased, which allows for liquid-phase epitaxy of GaN.

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Section: Resultsmentioning

confidence: 55%

“…However, the results showed that the growth rate was very low, and the uniformity was poor. After 60 h of growth, it was possible to observe pin holes as big as 10 μm …”

Section: Introductionmentioning

confidence: 99%

Liquid Phase Epitaxy of Gallium Nitride

Jaramillo-Cabanzo

Jasiński

Sunkara

2019

Crystal Growth & Design

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“…Typically, one requires about 20 atm pressure and 2000K temperature for dissolving nitrogen into gallium melts using molecular nitrogen according to reaction (1). Using plasma activation of nitrogen, the dissolution into gallium melts is favored at sub-atmospheric pressures and temperatures as low as 850 ºC according to reaction (2) 66,67 .…”

Section: Nitrogen-gallium Interaction In the Presence Of Plasmamentioning

confidence: 99%

Plasma catalysis using low melting point metals.

Carreon¹

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Plasma catalysis is emerging as one of the most promising alternatives to carry out several reactions of great environmental importance, from the synthesis of nanomaterials to chemicals of great interest. However, the combined effect of a catalyst and plasma is not clear. For the particular case of 1-D nanomaterials growth, the low temperatures synthesis is still a challenge to overcome for its scalable manufacturing on flexible substrates and thin metal foils. Herein, the use of low-melting-point metal clusters under plasma excitation was investigated to determine the effectiveness in their ability to catalyze the growth of 1-D nanomaterials. Specifically, plasma catalysis using Gallium (Ga) was studied for the growth of silicon nanowires. The synthesis experiments using silane in hydrogen flow over Ga droplets in the presence of plasma excitation yielded tip-led growth of silicon nanowires. In the absence of plasma, Ga droplets did not lead to silicon nanowire growth, indicating the plasma-catalyst synergistic effect when using Ga as catalyst. The resulting nanowires had a 1:1 droplet diameter to nanowire diameter relationship when the droplet diameters were less than 100 nm. From 100 nm to a micron, the ratio increased from 1:1 to 2:1 due to differences with wetting behavior as a function of droplet size. The growth vi experiments using Ga droplets derived from the reduction of Gallium oxide nanoparticles resulted in silicon nanowires with size distribution similar to that of Gallium oxide nanoparticles. Systematic experiments over 100 ºC-500 ºC range suggest that the lowest temperature for the synthesis of silicon nanowires using the plasma-gallium system is 200 ºC. A set of experiments using Ga alloys with aluminum and gold was also conducted. The results show that both Ga rich alloys (Ga-Al and Ga-Au) allowed the growth of silicon nanowires at a temperature as low as 200 ºC. This temperature is the lowest reported when using either pure Al or Au. The estimated activation energy barrier for silicon nanowire growth kinetics using AlGa alloy (~48.6 kJ/mol) was higher compared to that using either pure Ga or Ga-Au alloy (~34 kJ/mol). The interaction between Ga and hydrogen was measured experimentally by monitoring pressure changes in a Ga packed batch reactor at constant temperature. The decrease of the pressure inside the reactor when the Ga was exposed to plasma indicated the absorption of hydrogen in Ga. The opposite effect is observed when the plasma is turned off suggesting that hydrogen desorbed from Ga. This experimental observation suggests that Ga acts as hydrogen sink in the presence of plasma. The formation of Ga-H species in the Ga surface and in the bulk as intermediate is suggested to be responsible for the dehydrogenation of silyl radicals from the gas phase and subsequently for selective dissolution of silicon into molten Ga. The proposed reaction mechanism is also consistent with the experimentally determined activation barrier for growth kinetics (~34 kJ/mol). In addition, theoretical simulati...

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“…Because of this, it remains a challenge to grow GaN thin films from liquid solutions. 26,27 Despite the fact that metastable active nitrogen species, such as atomic nitrogen (𝑁), ionic nitrogen (𝑁 2 + ), and metastable molecular nitrogen (𝑁 2 * ), could improve solubility of nitrogen in liquid Ga, 28 this is irrelevant for the molecular beam epitaxy process in its vacuum and low temperature environment.…”

Section: Thin Film Growth Mechanisms and Associated Thermodynamic And...mentioning

confidence: 99%

Liquid-metal-enabled synthesis of aluminum-containing III-nitrides by plasma-assisted molecular beam epitaxy

Liang

Nuhfer

Towe

2016

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Nitride films are promising for advanced optoelectronic and electronic device applications. However, some challenges continue to impede development of high aluminum-containing devices. The two major difficulties are growth of high crystalline quality films with aluminum-rich compositions, and efficiently doping such films p-type.These problems have severely limited use of aluminum-rich nitride films grown by molecular beam epitaxy. A way around these problems is through use of a liquid-metalenabled approach to molecular beam epitaxy. Although the presence of a liquid metal layer at the growth front is reminiscent of conventional liquid phase epitaxy, this approach is different in its details. Conventional liquid epitaxy is a near-thermodynamic equilibrium process which liquid-metal assisted molecular beam epitaxy is not. Growth of aluminum-rich nitrides is primarily driven by the kinetics of the molecular vapor fluxes, and the surface diffusion of adatoms through a liquid metal layer before incorporation.This paper reports on growth of high crystalline quality and highly doped aluminumcontaining nitride films. Measured optical and electrical characterization data show that the approach is viable for growth of atomically smooth aluminum-containing nitride

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Plasma-assisted electroepitaxy of GaN layers from the liquid Ga melt

Cited by 10 publications

References 16 publications

Liquid Phase Epitaxy of Gallium Nitride

Liquid Phase Epitaxy of Gallium Nitride

Plasma catalysis using low melting point metals.

Liquid-metal-enabled synthesis of aluminum-containing III-nitrides by plasma-assisted molecular beam epitaxy

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