Chemical polishing of bulk and epitaxial GaN

Weyher, J.L.; Müller, Stefan; Grzegory, I.; Porowski, S.

doi:10.1016/s0022-0248(97)00320-5

Cited by 175 publications

(114 citation statements)

References 17 publications

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“…The removal of Ga from the surface, in this case, is most likely due to the formation and dissolution of Ga-based hydroxides. 12,13 In the study of semiconductors there have been many models developed to explain Fermi level pinning behavior. 14,15 One of these models proposed by Spicer et al describes Fermi level motion as being attributed to two bands of surface states, which correspond to Fermi level pinning positions associated with donor and acceptor character.…”

Section: Fig 2 ͑A͒mentioning

confidence: 99%

n- GaN surface treatments for metal contacts studied via x-ray photoemission spectroscopy

Rickert¹,

Ellis²,

Himpsel³

et al. 2002

Applied Physics Letters

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The surface chemistry and electronic properties of n-GaN surfaces were studied via x-ray photoemission spectroscopy before and after wet chemical treatments. Shifts of the surface Fermi level were measured with the change in position of the Ga 3d core level peak. HCl treatment of n-GaN led to a 0.9 eV shift of the surface Fermi level toward the conduction band minimum, while KOH treatment led to a 0.3 eV shift of the surface Fermi level toward the valance band maximum. These shifts lead to a reduction in the surface barrier for HCl-treated n-GaN and for KOH-treated p-GaN, potentially improving contact resistance. The changes in surface chemistry indicate that a N (or Ga) deficiency with HCl(KOH) treatment alters the surface state density through the formation of donor (acceptor)-like states.

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Section: Fig 2 ͑A͒mentioning

confidence: 99%

n- GaN surface treatments for metal contacts studied via x-ray photoemission spectroscopy

Rickert¹,

Ellis²,

Himpsel³

et al. 2002

Applied Physics Letters

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“…Due to the absence of inversion symmetry, the GaN substrate has two distinctly different crystal orientations -(0001) and (0001 ) corresponding to the Ga and N polarity respectively. The (0001 ) hexagonal face corresponding to the N-polarity is chemically active and therefore it could be prepared for epitaxy by mechano-chemical polishing [13], which gives atomically flat surfaces without subsurface damage. All the studies reported in our paper were obtained on this polarity.…”

Section: Methodsmentioning

confidence: 99%

Homo- and Hetero-Epitaxial Gallium Nitride Grown by Molecular Beam Epitaxy

Foxon

Cheng

Korakakis

et al. 1999

MRS Internet j. nitride semicond. res.

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Various methods have been used to initiate growth by Molecular Beam Epitaxy (MBE) of GaN on sapphire, or other substrates, but there is always a problem with morphology and with a high defect density which results in the formation of a sub-grain boundary structure. We show that by using, homo-epitaxial growth on properly prepared bulk GaN substrates, combined with high temperature growth, we obtain a significant improvement in surface morphology. Growth at sufficiently high temperature leads to a rapid smoothing of the surface and to almost atomically flat surfaces over relatively large areas. Multi-Quantum Well structures grown on such GaN epitaxial films are dislocation free with abrupt interfaces.

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“…One of the hexagonal surfaces of platelets were polished mechanochemically by the procedure described in [2]. Homoepitaxial GaN layers were deposited by metalorganic chemical vapor deposition (MOCVD) by standard procedures used up to now for the conductive GaN substrates [3].…”

Section: Crystal Growthmentioning

confidence: 99%

High Resistivity GaN Single Crystalline Substrates

et al. 1997

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High resistivity 104 -106 Ω cm (300 K) GaN single crystals were obtained by solution growth under high Ν2 pressure from melted Ga with 0.1-0.5at.% of Mg. Properties of these crystals are compared with properties of conductive crystals grown by a similar method from pure Ga melt. In • particular, it is shown that Mg-doped GaN crystals have better structural quality in terms of FWHM of X-ray rocking curve and low angle boundaries. Temperature dependence of electrical resistivity suggests hopping mechanism of conductivity. It is also shown that strain free GaN homoepitaxial layers can be grown on the Mg-doped GaN substrates.

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Chemical polishing of bulk and epitaxial GaN

Cited by 175 publications

References 17 publications

n- GaN surface treatments for metal contacts studied via x-ray photoemission spectroscopy

n- GaN surface treatments for metal contacts studied via x-ray photoemission spectroscopy

Homo- and Hetero-Epitaxial Gallium Nitride Grown by Molecular Beam Epitaxy

High Resistivity GaN Single Crystalline Substrates

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