Low Defect Density Bulk AlN Substrates for High Performance Electronics and Optoelectronics

Raghothamachar, Balaji; Dalmau, Rafael; Moody, Baxter; Craft, H. S.; Schlesser, R.; Xie, Jin Qiao; Collazo, Ramón; Dudley, Michael; Sitar, Zlatko

doi:10.4028/www.scientific.net/msf.717-720.1287

Cited by 28 publications

(21 citation statements)

References 10 publications

(6 reference statements)

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“…7,8 Accordingly, there is significant interest in AlN and AlN/ III-N alloys for numerous electronic, 9,10 opto-electronic, 11,12 electro-mechanical, 13,14 electro-acoustic, 15,16 and energy harvesting 17,18 device applications. Due to inherent economic advantages, significant interest exists for fabricating these and related AlN based devices on large diameter silicon (Si) substrates.…”

Section: Introductionmentioning

confidence: 99%

Band alignment at AlN/Si (111) and (001) interfaces

King

Nemanich

Davis

2015

Journal of Applied Physics

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Articles you may be interested inSmall valence-band offset of In 0.17 Al 0.83 N / GaN heterostructure grown by metal-organic vapor phase epitaxy Appl. Phys. Lett. 96, 132104 (2010); 10.1063/1.3368689 Band discontinuity in the GaAs/AlAs interface studied by in situ photoemission spectroscopy AlN and GaN epitaxial heterojunctions on 6H-SiC(0001): Valence band offsets and polarization fieldsDependence of (0001) GaN/AlN valence band discontinuity on growth temperature and surface reconstructionTo advance the development of III-V nitride on silicon heterostructure semiconductor devices, we have utilized in-situ x-ray photoelectron spectroscopy (XPS) to investigate the chemistry and valence band offset (VBO) at interfaces formed by gas source molecular beam epitaxy of AlN on Si (001) and (111) substrates. For the range of growth temperatures (600-1050 C) and Al pre-exposures (1-15 min) explored, XPS showed the formation of Si-N bonding at the AlN/Si interface in all cases. The AlN/Si VBO was determined to be À3.5 6 0.3 eV and independent of the Si orientation and degree of interfacial Si-N bond formation. The corresponding AlN/Si conduction band offset (CBO) was calculated to be 1.6 6 0.3 eV based on the measured VBO and band gap for wurtzite AlN. Utilizing these results, prior reports for the GaN/AlN band alignment, and transitive and commutative rules for VBOs, the VBO and CBO at the GaN/Si interface were determined to be À2.7 6 0.3 and À0.4 6 0.3 eV, respectively. V C 2015 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 99%

Band alignment at AlN/Si (111) and (001) interfaces

King

Nemanich

Davis

2015

Journal of Applied Physics

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“…In particular, the c-facet wafers cut from the freestanding AlN crystals contain a large N-polar (001-) facet, which presents a step-flow growth mode [30]. Compared with the Al-polar growth direction, the N-polar growth direction is preferable in favor of diameter enlargement and superior structural quality [30,31]. The c-facet wafers from (001-) grown AlN crystals with a low defect density are suitable as seeds for further N-polar seeded growth.…”

Section: Resultsmentioning

confidence: 99%

The Physical Vapor Transport Method for Bulk AlN Crystal Growth

et al. 2019

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In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.

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“…Moreover, for applications in power electronics, substrate sizes of at least 100 mm will be necessary to take advantage of the economy of scale and the advanced equipment of existing fabrication lines. While a slow but steady increase of wafer diameters can be achieved by repeated PVT bulk growth (Hartmann, 2013;Raghothamachar et al, 2012), limited data are available about the development of crystallographic defects along the axial ([0001] or [0001]) and lateral growth directions during diameter enlargement and the underlying mechanisms for defect formation. It has been pointed out (Hartmann et al, 2020) that a careful design of axial and radial temperature gradients in the growth zone is necessary to reduce the density of grown-in dislocations.…”

Section: Introductionmentioning

confidence: 99%

X-ray characterization of physical-vapor-transport-grown bulk AlN single crystals

et al. 2020

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AlN slices from bulk crystals grown under low thermomechanical stress conditions via the physical vapor transport (PVT) method were analyzed by X-ray methods to study the influence of the growth mode on the crystal quality. Defect types and densities were analyzed along axial [0001] as well as lateral growth directions. X-ray diffraction (0110) rocking-curve mappings of representative wafer cuts reveal a low mean FWHM of 13.4 arcsec, indicating the generally high crystal quality. The total dislocation density of 2 × 103 cm−2 as determined by X-ray topography is low and dislocations are largely threading edge dislocations of b = 1/3〈1120〉 type. The absence of basal plane dislocations in homogeneous crystal regions void of macroscopic defects can be linked to the low-stress growth conditions. Under the investigated growth conditions this high crystal quality can be maintained both along the axial [0001] direction and within lateral growth directions. Exceptions to this are some locally confined, misoriented grains and defect clusters, most of which are directly inherited from the seed or are formed due to the employed seed fixation technique on the outer periphery of the crystals. Seed-shaping experiments indicate no apparent kinetic limitations for an enhanced lateral expansion rate and the resulting crystal quality, specifically with regard to the growth mode on a-face facets.

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Low Defect Density Bulk AlN Substrates for High Performance Electronics and Optoelectronics

Cited by 28 publications

References 10 publications

Band alignment at AlN/Si (111) and (001) interfaces

Band alignment at AlN/Si (111) and (001) interfaces

The Physical Vapor Transport Method for Bulk AlN Crystal Growth

X-ray characterization of physical-vapor-transport-grown bulk AlN single crystals

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