Initial experiments in the migration enhanced afterglow growth of gallium and indium nitride

Butcher, Kenneth; Alexandrov, Dimiter; Terziyska, P.; Georgiev, Vasil; Georgieva, Dimka

doi:10.1002/pssc.201100209

Cited by 9 publications

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“…For the current experiments, the MEAglow [6][7][8] growth technique with pulsed metal precursor delivery has been used to help identify the physical processes that resulted from equipment changes; further details of film growth not found here can be found in the references cited. During this pulsed deposition, a metal layer is deposited and then subsequently nitrided with a nitrogen plasma to form a group III nitride semiconductor layer.…”

Section: Methodsmentioning

confidence: 99%

“…For the current experiments, a deposition technique with pulsed metalorganic delivery, "MEAglow" (Migration Enhanced Afterglow), [6][7][8] has been used to help identify the physical processes that resulted from the use of an RF plasma source operating at 13.56 MHz. In particular, we examined the case of GaN film growth for which there has been some past characterisation of metal adatom species on the surface.…”

Section: Introductionmentioning

confidence: 99%

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DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: Beyond ion bombardment effects

Butcher

Terziyska

Gergova

et al. 2017

Journal of Applied Physics

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It is shown that attractive electrostatic interactions between regions of positive charge in RF plasmas and the negative charge of metal wetting layers, present during compound semiconductor film growth, can have a greater influence than substrate temperature on film morphology. Using GaN and InN film growth as examples, the DC field component of a remote RF plasma is demonstrated to electrostatically affect metal wetting layers to the point of actually determining the mode of film growth. Examples of enhanced self-seeded nanopillar growth are provided in the case where the substrate is directly exposed to the DC field generated by the plasma. In another case, we show that electrostatic shielding of the DC field from the substrate can result in the growth of Ga-face GaN layers from gallium metal wetting layers at 490 C with root-mean-square roughness values as low as 0.6 nm. This study has been carried out using a migration enhanced deposition technique with pulsed delivery of the metal precursor allowing the identification of metal wetting layers versus metal droplets as a function of the quantity of metal source delivered per cycle. It is also shown that electrostatic interactions with the plasma can affect metal rich growth limits, causing metal droplet formation for lower metal flux than would otherwise occur. Accordingly, film growth rates can be increased when shielding the substrate from the positive charge region of the plasma. For the example shown here, growth rates were more than doubled using a shielding grid.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: Beyond ion bombardment effects

Butcher

Terziyska

Gergova

et al. 2017

Journal of Applied Physics

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“…[28] SiO 2 (PE-ALD) [7,24,25] β-Ga 2 O 3 (PE-ALD) [38] Silicon nitride (PE-ALD) [22,23,27,31,37,40] Plasma treatment (PE-ALD) [26] Electron treatment (CVD based) [36,39] GaN (CVD based) [42,44,45,55] InN (CVD based) [41][42][43]45,47,48,53,57,58] InGaN (CVD based) [49,51,54,56] InN nanopillars (CVD based) [46,50,52,55] The oxygen contamination overview provided in this introduction is followed by an experimental examination of some effects related to the surface modification of cathode materials by the generated plasma. In particular, we examine changes that have been observed for aluminum and stainless-steel cathodes.…”

Section: Materials (And Process) Referencementioning

confidence: 99%

“…Interest in the use of hollow cathodes for PE-ALD came about because of some low oxygen contamination results for GaN films grown using a relatively low-temperature means of deposition based on migration-enhanced epitaxy [42,44]. This is a pulsed method for deposition of GaN at temperatures below 670 • C, much lower than typical MOCVD growth temperatures of over 950 • C. However, ALD-like smoothness could be obtained with root mean square atomic force microscopy roughness measurements of below 1 nm [42,44,55] and, more importantly, when grown on GaN templates, oxygen contamination levels of ~10 16 cm −3 were measured by SIMS [42], similar to the levels of commercial MOCVDgrown material. Migration-enhanced epitaxy with a hollow cathode plasma source has also shown some excellent results for InN [41,42,47,48] and InGaN [49].…”

Section: Materials (And Process) Referencementioning

confidence: 99%

Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes

Butcher

Georgiev²,

Georgieva³

2021

Coatings

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Recent designs have allowed hollow cathode gas plasma sources to be adopted for use in plasma-enhanced atomic layer deposition with the benefit of lower oxygen contamination for non-oxide films (a brief review of this is provided). From a design perspective, the cathode metal is of particular interest since—for a given set of conditions—the metal work function should determine the density of electron emission that drives the hollow cathode effect. However, we found that relatively rapid surface modification of the metal cathodes in the first hour or more of operation has a stronger influence. Langmuir probe measurements and hollow cathode electrical characteristics were used to study nitrogen and oxygen plasma surface modification of aluminum and stainless-steel hollow cathodes. It was found that the nitridation and oxidation of these metal cathodes resulted in higher plasma densities, in some cases by more than an order of magnitude, and a wider range of pressure operation. Moreover, it was initially thought that the use of aluminum cathodes would not be practical for gas plasma applications, as aluminum is extremely soft and susceptible to sputtering; however, it was found that oxide and nitride modification of the surface could protect the cathodes from such problems, possibly making them viable.

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“…The theoretical conclusions are made on the basis of previous author's contributions [1,2]. The hetero-junctions are designed and technologically produced in the Semiconductor Research Laboratory at Lakehead University by new technology that is developed in this lab [3][4][5]. In fact, this type hetero-junction represents further development of this technology toward the development of electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Tunnel optical radiation in InxGa1−xN

Alexandrov¹,

Skerget²

2014

AIP Conference Proceedings

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An investigation of tunnel optical radiation in epitaxial layers of n-type In x Ga 1-x N grown on p-type GaN by novel plasma based migration enhanced epitaxy is presented. Experimental results of electro-luminescence spectra for n-In x Ga 1-x N/p-GaN hetero-junctions were obtained and they show two well expressed optical bandsone in range 500-540 nm and other in range 550-610 nm. An interesting detail is that each band begins and ends by sharp drops of the radiation, which nearly approach zero. A theoretical investigation of the unusual behavior of these spectra was done using LCAO electron band structure calculations. The optical ranges of these bands show that the radiation occurs in the In x Ga 1-x N region. In fact, substitutions of In atoms in Ga sites creates defects in the structure of In x Ga 1-x N and the corresponding LCAO matrix elements are found on this basis. The LCAO electron band structures are calculated considering the interactions between nearest-neighbor orbitals. Electron energy pockets are found in both the conduction and the valence bands at the Γ point of the electron band structures. Also it is found that these pockets are separated by distances, for which there is overlapping between the electron wave functions describing localized states belonging to the pockets, and as a result tunnel optical radiation can take place. This type of electron transitionbetween such a pocket in the conduction band and a pocket in the valence bandoccurs in In x Ga 1-x N, causing the above described optical bands. This conclusion concurs with the fact that the shapes of these bands change with change of the applied voltage.

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Initial experiments in the migration enhanced afterglow growth of gallium and indium nitride

Cited by 9 publications

References 0 publications

DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: Beyond ion bombardment effects

DC voltage fields generated by RF plasmas and their influence on film growth morphology through static attraction to metal wetting layers: Beyond ion bombardment effects

Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes

Tunnel optical radiation in InxGa1−xN

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