Plan-view image contrast of dislocations in GaN

Follstaedt, D. M.; Missert, Nancy A.; Koleske, Daniel; Mitchell, Christine C.; Cross, Karen Charlene

doi:10.1063/1.1632540

Cited by 69 publications

(44 citation statements)

References 17 publications

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“…The dislocation density measured on the surface of normal GaN by TEM was 9.1 ϫ 10 6 /cm 2 . A slightly lower dislocation density than the pit density was observed, and the difference is within the known TEM measurement error of 10% Follstaedt et al, 2003!. Briefly, the pits are considered to be the sites of dislocation, making a visible dislocation distribution on the optical microscopic scale.…”

Section: Resultsmentioning

confidence: 99%

Spatial Distribution of Dislocations in Relation to a Substructure in High-Quality GaN Film

Yang

Kim

et al. 2013

Microsc Microanal

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Abstract:The dislocation distribution of high-quality single-crystal gallium nitride~GaN! films grown by the hybrid vapor phase epitaxy was analyzed. This study examined the domain structure of GaN from the dislocation distribution on the macroscale by optical microscopy. The surface structure of GaN consisted of domains with microcolumns as the substructure. The inner domains contained a lower density of dislocations but a large number of these dislocations were observed along the domain boundaries. The existence of a domain boundary structure doubly increased the total dislocation density.

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Section: Resultsmentioning

confidence: 99%

Spatial Distribution of Dislocations in Relation to a Substructure in High-Quality GaN Film

Yang

Kim

et al. 2013

Microsc Microanal

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“…3 is a × μm AFM image of a GaN film, in which three kinds of pits of different sizes correspond to three different dislocations were observed. Three types of threading www.intechopen.com dislocations, edge, screw and mixed types are usually observed in wurtzite GaN epitaxial layers, with the corresponding Burgers vectors, confirmed by TEM (Follstaedt et al 2003 ;Datta et al 2004).…”

Section: Fig 1(a) Is Amentioning

confidence: 92%

AFM Application in III-Nitride Materials and Devices

Chen¹,

Su²,

Shi³

et al. 2012

Atomic Force Microscopy - Imaging, Measuring and Manipulating Surfaces at the Atomic Scale

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“…3.2. Since only the screw and edge components are measured, the partitioning between the screw, mixed, and edge dislocation densities is not possible [4], however, based on detailed TEM results approximately 11% of the dislocations are pure screw, 40% are mixed (screw and edge) and 49% are pure edge. As shown in Fig.…”

Section: Reducing Dislocation Density Of Gan Films On Sapphirementioning

confidence: 99%

Final report on LDRD project : outstanding challenges for AlGaInN MOCVD.

Mitchell¹,

Follstaedt²,

Russell³

et al. 2005

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The AlGaInN material system is used for virtually all advanced solid state lighting and short wavelength optoelectronic devices.Although metal-organic chemical vapor deposition (MOCVD) has proven to be the workhorse deposition technique, several outstanding scientific and technical challenges remain, which hinder progress and keep RD&A costs high. The three most significant MOCVD challenges are:(1) Accurate temperature measurement.(2) Reliable and reproducible p-doping (Mg).(3) Low dislocation density GaN material. To address challenge (1) we designed and tested (on reactor mockup) a multiwafer, dual wavelength, emissivity-correcting pyrometer (ECP) for AlGaInN MOCVD. This system simultaneously measures the reflectance (at 405 and 550 nm) and emissivity-corrected temperature for each individual wafer, with the platen signal entirely rejected. To address challenge (2) we measured the MgCp 2 + NH 3 adduct condensation phase diagram from 65-115°C, at typical MOCVD concentrations. Results indicate that it requires temperatures of 80-100°C in order to prevent MgCp 2 + NH 3 adduct condensation. Modification and testing of our research reactor will not be complete until FY2005. A new commercial Veeco reactor was installed in early FY2004, and after qualification growth experiments were conducted to improve the GaN quality using a delayed recovery technique, which addresses challenge (3). Using a delayed recovery technique, the dislocation densities determined from x-ray diffraction were reduced from 2x10 9 cm -2 to 4x10 8 cm -2 . We have also developed a model to simulate reflectance waveforms for GaN growth on sapphire.

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Plan-view image contrast of dislocations in GaN

Cited by 69 publications

References 17 publications

Spatial Distribution of Dislocations in Relation to a Substructure in High-Quality GaN Film

Spatial Distribution of Dislocations in Relation to a Substructure in High-Quality GaN Film

AFM Application in III-Nitride Materials and Devices

Final report on LDRD project : outstanding challenges for AlGaInN MOCVD.

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