Growth conditions and surface morphology of AlN MOVPE

Lobanova, A.V.; Yakovlev, E.V.; Талалаев, Р.А.; Thapa, S.B.; Scholz, F.

doi:10.1016/j.jcrysgro.2008.07.098

Cited by 39 publications

(29 citation statements)

References 17 publications

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“…The most common techniques used for AlN growth are metalorganic vapor phase epitaxy [9,10], hydride vapor phase epitaxy [11] and molecular beam epitaxy [12,13], all requiring expensive technology and high substrate temperature. Radio frequency (RF) reactive magnetron sputtering represents an attractive low-cost technique to synthesize AlN films, allowing deposition in a wide range of temperatures and in both rigid and flexible substrates [refs.…”

Section: Introductionmentioning

confidence: 99%

Two-step method for the deposition of AlN by radio frequency sputtering

et al. 2013

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This paper presents a detailed study of the influence of deposition conditions on structural and morphological properties of AlN thin films synthesized on c-sapphire substrates by radio frequency (RF) reactive sputtering. After the optimization of deposition parameters such as RF power and substrate temperature, the substrate bias has been identified as a critical variable to improve the structural properties of the AlN layers. The use of negative bias leads to a decrease of the full-width at half-maximum (FWHM) of the rocking curve of the AlN(0002) x-ray reflection and an increase of the grain size. However, 2θ/ω x-ray scans of layers grown under negative bias reveal lattice disorder at the AlN/sapphire interface, which is attributed to the highly accelerated positive ions (Al + , N + , N 2 + ) arriving to the substrate at the initial stages of the deposition process. In order to prevent this interface degradation, we propose a twostep deposition method which consists of starting the growth with an unbiased AlN buffer layer, at least 30 nm thick, followed by AlN deposition under negative bias. This procedure results in high-quality AlN layers with FWHM of the rocking curve of the (0002) reflection of 1.63°, grain size of~40 nm and root-mean-square surface roughness of 0.4 nm.

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Section: Introductionmentioning

confidence: 99%

Two-step method for the deposition of AlN by radio frequency sputtering

et al. 2013

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“…4 For all these applications, however, high-quality AlN is required. To grow such films various methods have been used including metalorganic chemical vapor deposition (MOCVD), 5 gas-source molecular-beam epitaxy (GSMBE), 6 and pulsed laser ablation, 7 all of which require high growth temperatures [T s (MOCVD, GSMBE) ‡ 1100°C and T s (laser ablation) ‡ 750°C] to achieve high-quality AlN. Also, due to the lack of bulk AlN substrates, heteroepitaxial growth has been employed using SiC, sapphire, and Si as the substrate, which, due to the large differences in thermal expansion coefficients of the materials, gives rise to large stress in the films leading to effects such as dislocations, wafer bowing, and cracks.…”

Section: Introductionmentioning

confidence: 99%

Structural Properties of AlN Grown on Sapphire at Plasma Self-Heating Conditions Using Reactive Magnetron Sputter Deposition

Seo

Petrov

Kim

2010

Journal of Elec Materi

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Aluminum nitride (AlN) films were grown on sapphire by reactive magnetron sputter deposition in N 2 discharges at plasma self-heating conditions. The growth temperature was as low as 94°C. The structural properties resulting from different substrate biases and growth pressures were investigated by atomic force microscopy, x-ray diffraction (XRD) measurements, and transmission electron microscopy (TEM). At 20 mTorr of N 2 with most sputtered species thermalized, films exhibited both AlN (0002) and ð1011Þ XRD peaks, with the AlN (0002) intensity initially increasing with ion energy above 15 eV, showing enhanced film quality with an optimum of 25 eV. At a lower growth pressure of 5 mTorr with energetic sputtered species, the AlN ð1011Þ peak disappeared and the crystallinity of AlN improved, exhibiting relaxed epitaxial AlN. The measured lattice parameter was 0.4975 nm, which was 0.10% smaller than that of bulk. The epitaxial relationship of a single-crystal AlN film was confirmed by pole figure and cross-sectional TEM. These results demonstrate that control of ion energy and energy of the sputter-deposited species is critical for film deposition at low temperature.

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“…Unfortunately, large lattice and thermal mismatches between AlN and sapphire lead to high dislocation densities in the epitaxial layers. On the other hand, the parasitic reactions between group-13 and group-15 precursors (also referred to as III and V), and the insufficient mobility of Al atoms are serious problems that need to be overcome for high-quality AlN growth, which deteriorate the structural and morphological quality of layers [4,5]. Therefore, researches have primarily focused on the growth of layers with an excellent crystalline quality and a smooth surface by various growth-techniques, -processes, and -parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Okada et al [1] expressed that thick-layer growth was found to be less effective in improving the crystalline quality of AlN layers. Lobanova et al [5] showed that flat surfaces are obtained at high temperature, a reduced growth rate, and an optimal V/III ratio. Recently, Banal et al [9] investigated the effect of the growth parameters for AlN directly grown on sapphire substrates by modified migration-enhanced epitaxy.…”

Section: Introductionmentioning

confidence: 99%

The influence of thickness and ammonia flow rate on the properties of AlN layers

Çörekçí

Öztürk

Çakmak

et al. 2012

Materials Science in Semiconductor Processing

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a b s t r a c tUndoped AlN layers have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition in order to study the effects of ammonia (NH 3 ) flow rate and layer thickness on the structural quality and surface morphology of AlN layers by highresolution X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Lower NH 3 flow rate improves crystallinity of the symmetric (0 0 0 2) plane in AlN layers. Ammonia flow rate is also correlated with surface quality; pit-free and smooth AlN surfaces have been obtained at a flow rate of 70 standard cm 3 per minute.Thicker AlN films improve the crystallinity of the asymmetric (1 0 1 2) plane.

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Growth conditions and surface morphology of AlN MOVPE

Cited by 39 publications

References 17 publications

Two-step method for the deposition of AlN by radio frequency sputtering

Two-step method for the deposition of AlN by radio frequency sputtering

Structural Properties of AlN Grown on Sapphire at Plasma Self-Heating Conditions Using Reactive Magnetron Sputter Deposition

The influence of thickness and ammonia flow rate on the properties of AlN layers

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