Optimization of a-plane GaN growth by MOCVD on r-plane sapphire

Ni, X.; Fu, Y.; Youngjoo, Moon; Bıyıklı, Necmi; Morkoç̌, H.

doi:10.1016/j.jcrysgro.2006.01.008

Cited by 141 publications

(147 citation statements)

References 10 publications

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“…Such anisotropic growth rates in the two orthogonal in-plane directions has been previously suggested for a-plane GaN films grown by MOVPE on r-plane sapphire. 13,40 In addition, Frank-Shockley-type partial dislocations could also contribute to the observed RC broadening. These dislocations bond the BPSFs and are expected to have anisotropic strain fields that will influence accordingly the RC broadening.…”

Section: -mentioning

confidence: 99%

Structural anisotropy of nonpolar and semipolar InN epitaxial layers

Darakchieva

Xie

Franco

et al. 2010

Journal of Applied Physics

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We present a detailed study of the structural characteristics of molecular beam epitaxy grown nonpolar InN films with a-and m-plane surface orientations on r-plane sapphire and ͑100͒ ␥-LiAlO 2 , respectively, and semipolar ͑1011͒ InN grown on r-plane sapphire. The on-axis rocking curve ͑RC͒ widths were found to exhibit anisotropic dependence on the azimuth angle with minima at InN ͓0001͔ for the a-plane films, and maxima at InN ͓0001͔ for the m-plane and semipolar films. The different contributions to the RC broadening are analyzed and discussed. The finite size of the crystallites and extended defects are suggested to be the dominant factors determining the RC anisotropy in a-plane InN, while surface roughness and curvature could not play a major role. Furthermore, strategy to reduce the anisotropy and magnitude of the tilt and minimize defect densities in a-plane InN films is suggested. In contrast to the nonpolar films, the semipolar InN was found to contain two domains nucleating on zinc-blende InN͑111͒A and InN͑111͒B faces. These two wurtzite domains develop with different growth rates, which was suggested to be a consequence of their different polarity. Both, a-and m-plane InN films have basal stacking fault densities similar or even lower compared to nonpolar InN grown on free-standing GaN substrates, indicating good prospects of heteroepitaxy on foreign substrates for the growth of InN-based devices.

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Section: -mentioning

confidence: 99%

Structural anisotropy of nonpolar and semipolar InN epitaxial layers

Darakchieva

Xie

Franco

et al. 2010

Journal of Applied Physics

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“…2,6,10,11,14,15,51 Nevertheless, the obtained widths of the rocking curves were much broader than that found in the low-strain materials produced by MOCVD and MBE, which indicate a large density of defects in the analyzed films.…”

Section: Discussionmentioning

confidence: 74%

“…[13][14][15][16] Differently, in reactive sputtering, the substrate temperature has a minor effect on the activation of the impinging species. Because of the relatively low working pressures of reactive sputtering, the activation of precursors is almost exclusively caused by the plasma, [17][18][19][20][21][22][23][24][25][26][27] and thus occurs independently of the substrate temperature.…”

Section: Discussionmentioning

confidence: 99%

“…5,[7][8][9] The main deposition techniques by which the highest quality films are produced with the highest control are molecular beam epitaxy (MBE) [10][11][12] and metalorganic chemical vapor deposition (MOCVD). [13][14][15][16] However, because these techniques are complex and expensive, the search for simpler and more versatile techniques capable of producing high quality homogeneous GaN films over large areas has attracted interest. 7,[17][18][19][20][21][22][23][24][25][26][27] Among the techniques under development for GaN growth based on physical processes are pulsed laser deposition (PLD) 28 and sputtering.…”

Section: Introductionmentioning

confidence: 99%

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Effects of substrate temperature, substrate orientation, and energetic atomic collisions on the structure of GaN films grown by reactive sputtering

Schiaber

Leite

Bortoleto

et al. 2013

Journal of Applied Physics

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Growth stresses and cracking in GaN films on (111) The combined effects of substrate temperature, substrate orientation, and energetic particle impingement on the structure of GaN films grown by reactive radio-frequency magnetron sputtering are investigated. Monte-Carlo based simulations are employed to analyze the energies of the species generated in the plasma and colliding with the growing surface. Polycrystalline films grown at temperatures ranging from 500 to 1000 C clearly showed a dependence of orientation texture and surface morphology on substrate orientation (c-and a-plane sapphire) in which the (0001) GaN planes were parallel to the substrate surface. A large increase in interplanar spacing associated with the increase in both a-and c-parameters of the hexagonal lattice and a redshift of the optical bandgap were observed at substrate temperatures higher than 600 C. The results showed that the tensile stresses produced during the film's growth in high-temperature deposition ranges were much larger than the expected compressive stresses caused by the difference in the thermal expansion coefficients of the film and substrate in the cool-down process after the film growth. The best films were deposited at 500 C, 30 W and 600 C, 45 W, which corresponds to conditions where the out diffusion from the film is low. Under these conditions the benefits of the temperature increase because of the decrease in defect density are greater than the problems caused by the strongly strained lattice that occurr at higher temperatures. The results are useful to the analysis of the growth conditions of GaN films by reactive sputtering. V C 2013 AIP Publishing LLC.

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“…Further, using a low temperature grown buffer layer [25], the films produced by MOCVD have resulted in substantially lower TDD on the order of 10 5 cm -2 even when grown on heterosubstrates. Although the MOCVD technique can produce high-quality films [26], the growth rate of this method is very low on the order of 1-2 µm/h only.…”

Section: (B) Metal Organic Chemical Vapor Deposition (Mocvd)mentioning

confidence: 99%

Vertical gallium nitride schottky diodes for power switching applications.

Kolli¹

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Optimization of a-plane GaN growth by MOCVD on r-plane sapphire

Cited by 141 publications

References 10 publications

Structural anisotropy of nonpolar and semipolar InN epitaxial layers

Structural anisotropy of nonpolar and semipolar InN epitaxial layers

Effects of substrate temperature, substrate orientation, and energetic atomic collisions on the structure of GaN films grown by reactive sputtering

Vertical gallium nitride schottky diodes for power switching applications.

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