High-quality coalescence of laterally overgrown GaN stripes on GaN/sapphire seed layers

Fini, P.; Zhao, Lingyan; Moran, B.; Hansen, M.; Marchand, H.; Ibbetson, J. P.; DenBaars, Steven P.; Mishra, Umesh K.; Speck, J. S.

doi:10.1063/1.124796

Cited by 112 publications

(68 citation statements)

References 14 publications

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“…This limits the substrate size to a square of 10×10 mm 2 (ref. [5][6][7], and thus is extremely expensive. Therefore, it would be impractical for industry.…”

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confidence: 99%

Defect reduction in overgrown semi-polar (11-22) GaN on a regularly arrayed micro-rod array template

et al. 2016

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We demonstrate a great improvement in the crystal quality of our semi-polar (11-22) GaN overgrown on regularly arrayed micro-rod templates fabricated using a combination of industry-matched photolithography and dry-etching techniques. As a result of our micro-rod configuration specially designed, an intrinsic issue on the anisotropic growth rate which is a great challenge in conventional overgrowth technique for semi-polar GaN has been resolved. Transmission electron microscopy measurements show a different mechanism of defect reduction from conventional overgrowth techniques and also demonstrate major advantages of our approach. The dislocations existing in the GaN micro-rods are effectively blocked by both a SiO2 mask on the top of each GaN micro-rod and lateral growth along the c-direction, where the growth rate along the c-direction is faster than that along any other direction. Basal stacking faults (BSFs) are also effectively impeded, leading to a distribution of BSF-free regions periodically spaced by BSF regions along the [-1-123] direction, in which high and low BSF density areas further show a periodic distribution along the [1-100] direction. Furthermore, a defect reduction model is proposed for further improvement in the crystalline quality of overgrown (11-22) GaN on sapphire.

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“…This limits the substrate size to a square of 10×10 mm 2 (ref. [5][6][7], and thus is extremely expensive. Therefore, it would be impractical for industry.…”

mentioning

confidence: 99%

Defect reduction in overgrown semi-polar (11-22) GaN on a regularly arrayed micro-rod array template

et al. 2016

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“…A high lateral overgrowth rate, as well as vertical facets, is typically chosen for smooth and rapid coalescence. 8 The growth and structure of LEO GaN materials have been studied through control of many growth parameters, such as the growth temperature, 9 mask orientation, 10,11 V/III ratio, 12 mask fill factors, 12 and with Mg and Si doping. 13 In this work, a small amount addition of Sb was found to increase the lateral overgrowth rate and result in vertical facets under conditions that normally produce triangular or sloped sidewalls over a range of growth temperatures.…”

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confidence: 99%

Effect of Sb as a surfactant during the lateral epitaxial overgrowth of GaN by metalorganic vapor phase epitaxy

Zhang

Tang

Kuech

2001

Applied Physics Letters

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Antimony ͑Sb͒, an isoelectronic impurity, has been studied as a surfactant during the lateral epitaxial overgrowth ͑LEO͒ of gallium nitride ͑GaN͒ by metalorganic vapor phase epitaxy ͑MOVPE͒. The presence of Sb in the gas phase was found to alter both the LEO growth rates and the predominant facet formations. Vertical facets to the LEO growth appear with the addition of Sb under conditions that normally produce triangular or sloped sidewalls over a range of growth temperatures. While Sb alters the growth facets, only a small amount of Sb was incorporated into the GaN, suggesting that Sb acts as a surfactant during the GaN MOVPE growth. Sb addition produces surface conditions characteristic of a Ga-rich surface stoichiometry indicating both a possible change in the reactivity of NH 3 and/or enhanced surface diffusion of Ga adatom species. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1415774͔The use of a suitable impurity, as a surfactant, during the growth of semiconductor films has attracted increasing interest in recent years. [1][2][3][4][5][6] Elemental surfactants are typically characterized by low vapor pressure and low solubility in the solid. They can segregate to the surface and affect surface properties, such as the surface energy, reconstruction and surface kinetic processes of the growing surface. As a result, a small amount of surfactant impurities can significantly alter the growth characteristics and change the resulting film structure without a high level of incorporation into the films. For example, in the case of SiGe growth, antimony ͑Sb͒ has been known to both segregate to the growth front and alter the surface energy of the SiGe. This change in surface energy results in an increase in the epitaxial thickness of the SiGe layer and facilitates layer by layer growth with respect to island growth. 1,2 In this letter, we describe the use of the Sb isoelectronic center as a surfactant during the lateral epitaxial overgrowth ͑LEO͒ of gallium nitride ͑GaN͒ by metalorganic vapor phase epitaxy ͑MOVPE͒.GaN and related materials have been extensively investigated for applications to short wavelength optoelectronics and high temperature and high power electronics. One of the main issues in the GaN crystal growth is the reduction in the threading dislocation density arising from the large lattice mismatch between the GaN film and underlying substrate. The LEO growth technique has been reported as a route for achieving GaN with a significant reduction in the dislocation density. Long-lifetime GaN laser diodes fabricated on LEOgrown materials have been demonstrated. 7 In these applications, it is desirable to increase the yield of the high quality GaN materials in the lateral overgrowth region. A high lateral overgrowth rate, as well as vertical facets, is typically chosen for smooth and rapid coalescence. 8 The growth and structure of LEO GaN materials have been studied through control of many growth parameters, such as the growth temperature, 9 mask orientation, 10,11 V/III ratio, 12 mask fill fact...

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“…In some cases (e.g. in GaN on sapphire ELO 103s structures) the values of the tilt angle A~max in excess of 20 are reported [32]. So large tilts cannot be accom-104 modated elastically, i.e.…”

Section: Gaas Substrateqmentioning

confidence: 99%

Laterally overgrown structures as substrates for lattice mismatched epitaxy

Żytkiewicz

2002

Thin Solid Films

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High-quality coalescence of laterally overgrown GaN stripes on GaN/sapphire seed layers

Cited by 112 publications

References 14 publications

Defect reduction in overgrown semi-polar (11-22) GaN on a regularly arrayed micro-rod array template

Defect reduction in overgrown semi-polar (11-22) GaN on a regularly arrayed micro-rod array template

Effect of Sb as a surfactant during the lateral epitaxial overgrowth of GaN by metalorganic vapor phase epitaxy

Laterally overgrown structures as substrates for lattice mismatched epitaxy

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