Growth evolution and microstructural characterization of semipolar (112̄2) GaN selectively grown on etched r-plane sapphire

Leung, Benjamin; Sun, Qian; Yerino, Christopher D.; Han, Jung; Kong, Bo Hyun; Cho, Hyung Koun; Liao, Kuan-Yung; Li, Yun-Li

doi:10.1016/j.jcrysgro.2011.12.035

Cited by 21 publications

(24 citation statements)

References 37 publications

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“…A low-temperature AlN (LTAlN) buffer is used to initiate growth. As reported earlier, 16 the LT-AlN buffer is deposited on all surfaces, but the subsequent GaN growth favors nucleation and growth off of the c-oriented AlN formed on the (0001)-oriented sidewall. Growth is performed at a growth rate of 3.6 lm/h to a total growth thickness of 10.5 lm.…”

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confidence: 63%

“…8 The high relative intensity of NBE to BSF related emission (NBE to BSF intensity ratio of 2.8), and the narrow linewidth of the GaN bandedge emission of 14 meV indicate high microstructural quality, especially when compared to semipolar or nonpolar GaN on planar sapphire substrates. 8,9,26 Further, techniques such crystal shaping for defect bending and blocking 16,27 and use of in-situ grown interlayers 28,29 have shown additional improvement in microstructural quality with growth on patterned sapphire is possible.…”

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confidence: 99%

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Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates

Leung

Wang

Kuo

et al. 2014

Applied Physics Letters

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Here, we demonstrate a process to produce planar semipolar (202¯1) GaN templates on sapphire substrates. We obtain (202¯1) oriented GaN by inclined c-plane sidewall growth from etched sapphire, resulting in single crystal material with on-axis x-ray diffraction linewidth below 200 arc sec. The surface, composed of (101¯1) and (101¯0) facets, is planarized by the chemical-mechanical polishing of full 2 in. wafers, with a final surface root mean square roughness of <0.5 nm. We then analyze facet formation and roughening mechanisms on the (202¯1) surface and establish a growth condition in N2 carrier gas to maintain a planar surface for further device layer growth. Finally, the capability of these semipolar (202¯1) GaN templates to produce high quality device structures is verified by the growth and characterization of InGaN/GaN multiple quantum well structures. It is expected that the methods shown here can enable the benefits of using semipolar orientations in a scalable and practical process and can be readily extended to achieve devices on surfaces using any orientation of semipolar GaN on sapphire.

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confidence: 63%

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confidence: 99%

Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates

Leung

Wang

Kuo

et al. 2014

Applied Physics Letters

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“…The NL thus plays a very crucial role to control selectivity with respect to the surface orientation. However, the complete single selectivity of growth direction is broken when reducing the reactor pressure below 60 mbar [7,15]. Both vertical growth from the spacings and inclined growth from the sidewalls exist simultaneously and compete.…”

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confidence: 99%

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confidence: 99%

“…Epitaxial lateral overgrowth (ELOG) is the most popular approach to overcome these problems [3][4][5]. Semi-polar ð1122Þ GaN has for example been grown on stripe patterned sapphire substrate to reduce the TDD and BSF density [6][7][8].A-plane ð1120Þ GaN on the r-plane (1102) flat sapphire substrates (FSS) is generally grown by the two-step growth approach also employed for the c-plane growth. This includes a low temperature nucleation layer (NL) and high temperature overlayer [9][10][11].…”

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Phase control of semi-polar and non-polar GaN on cone shaped r-plane patterned sapphire substrates

Wang

Brunner

Liao

et al. 2013

Journal of Crystal Growth

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Study of high‐quality (11−22) semi‐polar GaN grown on nanorod templates

Gong

et al. 2015

Physica Status Solidi (b)

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(11−22) semi‐polar GaN overgrown on nanorod templates with different nanorod diameters has been systematically studied in terms of crystal quality, strain relaxation, wafer bowing and electrical properties. With increasing nanorod diameter from 300 to 827 nm, the full width at half maximum (FWHM) of the X‐ray rocking curve reduces from 0.20° to 0.15° along (1−100) direction and from 0.15° to 0.10° along (11−2−3) direction, respectively. The strain relaxation of the overgrown GaN layers has been significantly enhanced, leading to a reduction in wafer bowing from 0.0298 to 0.0091 cm−1. The electron mobility in the overgrown GaN layers increases from 83 to 228 cm V−1 s−1 and from 52 to 124 cm V−1 s−1 along (1−100) and (11−2−3) directions, respectively.

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Growth evolution and microstructural characterization of semipolar (112̄2) GaN selectively grown on etched r-plane sapphire

Cited by 21 publications

References 37 publications

Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates

Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates

Phase control of semi-polar and non-polar GaN on cone shaped r-plane patterned sapphire substrates

Study of high‐quality (11−22) semi‐polar GaN grown on nanorod templates

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