Role of the buffer layer thickness on the formation of basal plane stacking faults in a-plane GaN epitaxy on r-sapphire

Wu, Zhihao; Fischer, Alec M.; Ponce, Fernando; Yokogawa, Toshiya; Yoshida, Shunji; Kato, Ryo

doi:10.1063/1.2953082

Cited by 25 publications

(23 citation statements)

References 13 publications

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“…1(c) and (d). It is known that irregular size and anisotropic shape of nucleus results in a high density of partial dislocations, which is originated from the in-plane anisotropic strains of c-and m-directions [18]. Therefore AFM images of NLs indicated that a stable nucleation can be initiated at the thickness of 120 nm.…”

Section: Resultsmentioning

confidence: 98%

“…To optimize the growth conditions and analyze growth behaviors of a-plane GaN on sapphire substrates, the surface and structural properties of a-plane GaN films were characterized by using atomic force microscopy (AFM), high resolution X-ray diffraction (HR-XRD), and transmission electron microscopy (TEM). (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) a-plane GaN films were grown on (1-102) r-plane sapphire substrates by using an AXITRON 11 Â 2 in. metal-organic chemical vapor deposition system based on planetary reactor.…”

Section: Introductionmentioning

confidence: 99%

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Growth of high quality a-plane GaN epi-layer on r-plane sapphire substrates with optimization of multi-buffer layer

Song

Suh

Kim

et al. 2010

Journal of Crystal Growth

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Growth of high quality a-plane GaN epi-layer on r-plane sapphire substrates with optimization of multi-buffer layer

Song

Suh

Kim

et al. 2010

Journal of Crystal Growth

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“…There is a good lattice match along [0001] GaN//[1-101] Al 2 O 3 , while lattice mismatch is 16% along the [1-100] GaN// [11-20] Al 2 O 3 crystal directions. Furthermore, the growth rate along the c-direction is much higher than that along the m-direction, so the pleat morphology comes forth and produces the anisotropy [7,8].…”

Section: Resultsmentioning

confidence: 98%

Optical and electrical properties of Si-doped in a-plane GaN grown on r-plane sapphire

Zhou

Yang

et al. 2010

Sci. China Technol. Sci.

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a-plane GaN grown on (1-102) r-plane sapphire substrate was obtained by metal organic chemical vapor deposition. The optical and electrical properties of the Si-doped a-plane GaN films were investigated by photoluminescence spectroscopy, high-resolution X-ray diffraction, atomic force microscopy and Hall measurement. The results showed that the morphology and the crystal quality slightly degraded with Si doping. The yellow luminescence was enhanced with increasing the flow rate of the SiH 4 . The significant improvement of the mobility should associate with some of the vacancy filled with the Si. GaN, nonpolar, dislocation, photoluminescenceCitation: Xu S R, Zhou X W, Hao Y, et al. Optical and electrical properties of Si-doped in a-plane GaN grown on r-plane sapphire.AlGaN/GaN heterostructures have shown the excellent properties in advanced power and optoelectronic devices, such as high electron mobility transistors (HEMTs) and light-emitting diodes (LEDs). It has also been found that the wurtzite phase AlGaN/GaN exhibits huge spontaneous and piezoelectronic polarization effects that negatively impact the performance of LED. It is due to that the spatial separation of electrons and holes in quantum well with c-axis orientation seriously reduces the oscillator strength thereby causes a redshift of emission wavelength, which is called the quantum confined Stark effect. On the other hand, the extra-ordinarily high polarization charges make it difficult to enable normally-off operations on the c-plane face. To circumvent this problem, a material growth with non-polar crystal orientation was developed [1-3]. Masayuki et al. analyzed a non-polar type a-plane (11-20) AlGaN/GaN HFET free from polarization, and concluded that the polarization was not formed perpendicular to the heterointerface so the device could allow nearly normally-off operations [4]. However, the extended defect densities in non-polar a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) GaN were yet very high according to the state-of-the-art of material growth technology. For the a-plane (11-20) GaN on r-plane (1-102) grown by metal organic chemical vapor deposition (MOCVD), there occurred a TD density of 3×10 10 cm −2 and a basal stacking fault density of 3.5×10 5 cm −1 [5]. So the electron mobility of the as-grown a-plane GaN films was very low. It was only 5.14 cm 2 /Vs in Masayuki Kuroda's work. In this paper, a-plane GaN films with different Si doping concentrations were grown by MOCVD. Their optical, surface morphology, structural and electrical properties were studied by photoluminescence spectrum (PL), atomic force microscopy (AFM), high-resolution X-ray diffraction (HRXRD) and Hall measurements.

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“…This is due to the elimination of the strong built-in electric fields which play a role in limiting the radiative recombination efficiency of c-plane structures. However, it is now well established that non-polar films grown on foreign substrates such as r-plane sapphire and γ-LiAlO 2 suffer from high densities of threading dislocations and basal-plane stacking faults (BSFs) [1]. BSFs are extended planar defects that lie in the c-plane and can be considered as narrow inclusions of cubic phase (ZB) material in a wurtzite (WZ) matrix.…”

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confidence: 99%

Carrier dynamics in non‐polar GaN/AlGaN quantum wells intersected by basal‐plane stacking faults

Badcock

Hammersley

Kappers

et al. 2010

Phys. Status Solidi (c)

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We have investigated the recombination dynamics of carriers in non‐polar GaN/AlGaN quantum wells intersected by basal plane stacking faults and an a ‐plane GaN template layer. In the GaN template, both the photoluminescence decay and rise times measured across the basal plane stacking fault emission band increase with decreasing emission energy. This is consistent with a carrier transfer process from less localised to more deeply localised states within the basal plane stacking fault. However, in the quantum well structures this behaviour is suppressed due to the restriction in carrier transport imposed by the quantum wells. We also found that the decay time of the localised exciton emission in the quantum wells is dominated by a non radiative carrier transfer process involving the basal plane stacking faults. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Role of the buffer layer thickness on the formation of basal plane stacking faults in a-plane GaN epitaxy on r-sapphire

Abstract: Optical properties of nearly stacking-fault-free m -plane GaN homoepitaxial films grown by metal organic vapor phase epitaxy on low defect density freestanding GaN substrates

Cited by 25 publications

References 13 publications

Growth of high quality a-plane GaN epi-layer on r-plane sapphire substrates with optimization of multi-buffer layer

Growth of high quality a-plane GaN epi-layer on r-plane sapphire substrates with optimization of multi-buffer layer

Optical and electrical properties of Si-doped in a-plane GaN grown on r-plane sapphire

Carrier dynamics in non‐polar GaN/AlGaN quantum wells intersected by basal‐plane stacking faults

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