Selective Area Growth of GaN Using Tungsten Mask by Metalorganic Vapor Phase Epitaxy

Kawaguchi, Yôichi; Nambu, Shingo; Sone, H.; Shibata, T.; Matsushima, Hidetada; Yamaguchi, M.; Miyake, Hideto; Hiramatsu, Kazumasa; Sawaki, Nobuhiko

doi:10.1143/jjap.37.l845

Cited by 36 publications

(21 citation statements)

References 15 publications

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“…GaN growth is initiated only on the Ga 2 O 3 template and results in a lateral growth over the AlO x stripe. W was used in place of SiO 2 or silicon nitride as mask and, at first sight, leads to similar results, although W reacts somehow with ammonia at the growth temperature [113,114]. However, the tilting of the c-axis direction is smaller when using a W mask instead of SiO 2 [78,114].…”

Section: New Developmentsmentioning

confidence: 85%

Epitaxial Lateral Overgrowth of GaN

Beaumont

Vennéguès

Gibart

2001

phys. stat. sol. (b)

191

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Since there is no GaN bulk single crystal available, the whole technological development of GaN based devices relies on heteroepitaxy. Numerous defects are generated in the heteroepitaxy of GaN on sapphire or 6H‐SiC, mainly threading dislocations (TDs). Three types of TDs are currently observed, a type (with Burgers vector 1/3〈$11 \bar{2}0$〉); c type (with 〈0001〉) and mixed a+c (1/3〈$11 \bar{2}3$〉). The Epitaxial Lateral Overgrowth (ELO) technology produces high quality GaN with TD densities in the mid 106 cm—2, linewidth of the low‐temperature photoluminescence (PL) near‐bandgap recombination peaks <1 meV and deep electron traps reduced below 1014 cm—3 (compared to mid 1015 cm—3 in standard GaN). Numerous modifications of the ELO process have been proposed in order either to avoid technological steps (mask‐less ELO) or to improve it (pendeo‐epitaxy). Basically developed on either sapphire or 6H‐SiC, the ELO technology is also achievable on (111)Si or (111)3C‐SiC/Si provided that an appropriate buffer layer is grown to avoid cracks. More sophisticated technologies have been implemented to further increase the useable part of the ELO GaN surface (two technological steps, three‐step ELO). Unfortunately, in‐depth understanding of the basic ELO process is still missing, i.e. of the growth anisotropy and bending of dislocations.

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Section: New Developmentsmentioning

confidence: 85%

Epitaxial Lateral Overgrowth of GaN

Beaumont

Vennéguès

Gibart

2001

phys. stat. sol. (b)

191

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“…After 15 mm distance to the substrate facet growth stops and only perfect h0001i growth occurs both between and above the tungsten stripes. Accordingly, at the sample surface no influence of the mask position is detected in the luminescence, showing the main excitonic line at 357 nm [4,5]. This is directly visualized in Fig.…”

mentioning

confidence: 56%

“…The ELO approach consists of masking parts of the defective crystalline substrate GaN "seed" layer with an amorphous layer preventing the dislocations from propagating into the overlayer during subsequent re-growth. While impurities are unintentional incorporated in the initial stages of ELOG, the biaxial strain and defect concentration are reduced on the top of the mask [2][3][4][5].The maskless heteroepitaxy on pre-patterned substrates has been proven successful in achieving crack free AlGaN on trench-patterned GaN/sapphire substrates [6,7]. …”

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confidence: 99%

Optical Micro-Characterization of Complex GaN Structures

Christen

Riemann

2001

phys. stat. sol. (b)

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Various techniques of pattern-controlled epitaxy like epitaxial lateral overgrowth (ELO) and lateral seeding epitaxy have successfully been used to overcome the lattice mismatch problem, however, resulting in a complex system of self-organized growth domains. For a detailed understanding a correlation of the structural, electronic, and optical properties on a micro-scale is mandatory. Scanning cathodoluminescence (CL) microscopy provides a powerful tool compiling low temperatures, spatial resolution Dx < 45 nm and high spectral resolution. ELO GaN on stripe patterned SiO 2 and W masks were characterized by CL microscopy, directly visualizing the formation of different growth domains: 1. the coherently grown regions between the stripes; 2. the ELO areas coalescing on the center of the masks and showing a blue shifted and strongly broadened CL where m-Raman evidences the reduction of local strain and probes the free carrier concentration which is dramatically changed over the masks; 3. the coalescence regions with poor epitaxial perfection including voids and strong incorporation of impurities; 4. the transition regions between 1. and 2. at the very edges of the masks characterized by high defect density and strongly blue shifted CL. Plan view CL directly images the local areas of improved crystal perfection only involving part of the total ELO regions. The formation of specific micro-domains in 5 mm thick crack-free Al 0.19 Ga 0.81 N, exhibiting different Al concentrations, during the initial stage of MOVPE grown on patterned GaN substrates and the transition to finally homogeneous growth is directly visualized by cross-sectional CL.Introduction For a detailed understanding of complex semiconductor heterostructures and the physics of devices based on them a systematic determination and correlation of the structural, chemical, electronic, and optical properties on a micro-or nanoscale is essential. Luminescence techniques belong to the most sensitive, non-destructive methods of analyzing both, intrinsic and extrinsic semiconductor properties. Combining the luminescence spectroscopy with the high spatial resolution of a scanning electron microscope (SEM), realized by the technique of cathodoluminescence (CL) microscopy, provides a powerful tool for the nano-characterization of semiconductors, their heterostructures as well as their interfaces [1].Employing the technique of Epitaxial Lateral Overgrowth (ELO) to the group-III nitrides has been proven successful in significantly reducing the concentration of threading dislocations emanating from the underlying buffer layer. The ELO approach consists of masking parts of the defective crystalline substrate GaN "seed" layer with an amorphous layer preventing the dislocations from propagating into the overlayer during subsequent re-growth. While impurities are unintentional incorporated in the initial stages of ELOG, the biaxial strain and defect concentration are reduced on the top of the mask [2][3][4][5].The maskless heteroepitaxy on pre-patterned substrates has been pr...

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“…In the previous work, we succeeded in the SAG of GaN using W masks by MOVPE for the first time [12]. In this work, we compare the W mask and the SiO 2 mask in terms of shape and crystalline quality of the SAG-GaN.…”

Section: Resultsmentioning

confidence: 99%

“…In a previous study, we attempted the SAG of GaN using tungsten (W) masks by metalorganic vapor phase epitaxy (MOVPE) for the first time [12]. In this study, we compare the SAG of GaN using W mask to that of SiO 2 mask by MOVPE by means of scanning electron microscope (SEM) and cathodoluminescence (CL) measurements.…”

Section: Introductionmentioning

confidence: 99%

Selective Area Growth (SAG) and Epitaxial Lateral Overgrowth (ELO) of GaN using Tungsten Mask

Kawaguchi

Nambu

Sone

et al. 1999

MRS Internet j. nitride semicond. res.

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Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of GaN using tungsten (W) mask by metalorganic vapor phase epitaxy (MOVPE) and hydride vapor phase epitaxy (HVPE) have been studied. The selectivity of the GaN growth on the W mask as well as the SiO 2 mask is excellent for both MOVPE and HVPE. The ELO-GaN layers are successfully obtained by HVPE on the stripe patterns along the < > 1 1 00 crystal axis with the W mask as well as the SiO 2 mask. There are no voids between the SiO 2 mask and the overgrown GaN layer, while there are triangular voids between the W mask and the overgrown layer. The surface of the ELO-GaN layer is quite uniform for both mask materials. In the case of MOVPE, the structures of ELO layers on the W mask are the same as those on the SiO 2 mask for the < > 1120 and < > 1 1 00 stripe patterns. No voids are observed between the W or SiO 2 mask and the overgrown GaN layer by using MOVPE.

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Selective Area Growth of GaN Using Tungsten Mask by Metalorganic Vapor Phase Epitaxy

Cited by 36 publications

References 15 publications

Epitaxial Lateral Overgrowth of GaN

Epitaxial Lateral Overgrowth of GaN

Optical Micro-Characterization of Complex GaN Structures

Selective Area Growth (SAG) and Epitaxial Lateral Overgrowth (ELO) of GaN using Tungsten Mask

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