In situ control of gan growth by molecular beam epitaxy

Held, R.; Crawford, D.; Johnston, A. M.; Dabiran, A. M.; Cohen, P. I.

doi:10.1007/s11664-997-0163-z

Cited by 74 publications

(52 citation statements)

References 10 publications

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“…Nevertheless, we do agree with their result that the indium strongly segregates to the surface. We note that the results of Widmann et al apply probably to Ga-polar films (they used an AlN buffer layer, which tends to produce Ga-polar material [6]), whereas our result is for N-polar films. Future studies of Ga-polar InGaN films are planned, in order to more completely understand the role of indium in the growth kinetics.…”

Section: Indium-covered (000 ) Surfacescontrasting

confidence: 68%

“…In the former, the RHEED pattern is streaky, indicative of flat morphology, and in the latter the RHEED pattern is spotty indicative of rough surface morphology. This behavior has been noted by a number of authors [6,16], and indeed, the transition from smooth to rough is generally used as a definition of Ga-rich compared to N-rich growth. AFM imaging has been used to image this smooth to rough behavior in real-space [16]; our results for this morphological change are pictured in Fig.…”

Section: Growth Kinetics On Bare Surfacesmentioning

confidence: 60%

“…More comprehensive work combining STM and firstprinciples theoretical computations was used by our group to identify the surface reconstructions for both the Ga-polar (0001) and the N-polar (000 ) surfaces, prepared by molecular beam epitaxy (MBE) [3][4][5]. Detailed work by Held et al using thermal desorption spectroscopy has provided valuable information on the gallium coverage of GaN during growth [6]. Photoemission spectroscopy has revealed the presence of well defined dangling bond states on the surface, although the geometry (and polarity) of the surfaces studied there was not clear [7,8].…”

Section: Introductionmentioning

confidence: 99%

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Reconstructions of GaN and InGaN surfaces

Feenstra

Chen

Vidhya

et al. 2000

Applied Surface Science

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The reconstruction and growth kinetics of gallium nitride (0001) and (000 ) surfaces are studied using scanning tunneling microscopy, reflection high-energy electron diffraction, and low-energy electron diffraction. Results for bare GaN surfaces are summarized, with particular attention paid to the "pseudo-1×1" reconstruction of the (0001) face. Changes in the surface structure and kinetic processes due to indium co-deposition during growth are discussed.

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Section: Indium-covered (000 ) Surfacescontrasting

confidence: 68%

Section: Growth Kinetics On Bare Surfacesmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

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Reconstructions of GaN and InGaN surfaces

Feenstra

Chen

Vidhya

et al. 2000

Applied Surface Science

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“…Now, Molecular Beam Epitaxy (MBE) also plays an important role in growth of nitrides. This is due, in part, to the possibility of detailed studies of the growth process with standard MBE toolsReflection High Energy Electron Diffraction (RHEED) and Desorption Mass Spectrometry (DMS) [5] [6] [7] [8] [9]. Additional progress has been achieved in the last few years by implementation in MBE of gaseous ammonia as the source of reactive nitrogen [10] [11] [12] [13].…”

Section: Introductionmentioning

confidence: 99%

The role of gaseous species in group-III nitride growth

Karpov¹,

Makarov

Ramm

1997

MRS Internet j. nitride semicond. res.

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A quasi-thermodynamic model accounting for kinetics of molecular nitrogen evaporation is applied to simulate the growth of binary and ternary group-III nitrides using atomic group-III elements and molecular ammonia as the sources. The values of the molecular nitrogen evaporation coefficients from the surface of GaN and AlN necessary for the simulation are extracted from experiments on free evaporation of the crystals in vacuum, while for InN only estimates are available. The growth process of AlN and InN is studied by analyzing the composition of the desorbed vapor species that are thought to influence the native defect formation in group-III nitrides. Different channels of desorption from the surfaces of group-III nitrides (related either to group-III atoms or to their hydrides) are compared. Specific features of the growth processes under the metal-rich and N-rich conditions are analyzed. The developed approach is extended to study the growth of the ternary compounds GaInN and AlGaN. The growth rate of ternary compounds versus temperature shows a two-drop behavior corresponding to the rapid increase of the respective group-III atom desorption. The effect is accompanied by a corresponding stepwise change in the solid phase composition. Factors retarding the growth of ternary compounds -the miscibility gap related to internal strain accumulated in the solid phase due to the lattice mismatch of binary constituents, and the extra liquid phase formation during growth -are discussed with respect to GaInN.

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“…The influence of critical growth parameters such as V/III ratio and substrate temperature on the surface morphology, electrical and optical properties of GaN films has been studied extensively [1][2][3][4][5][6]. In many cases, however, the obtained results are specific for particular growth methods and do not provide the insight into general tendencies of the growth process.…”

Section: Introductionmentioning

confidence: 99%

CRYSTAL STRUCTURE AND DEFECTS IN NITROGEN-DEFICIENT GaN

Oktyabrsky¹,

Dovidenko²,

Sharma³

et al. 1999

MRS Internet j. nitride semicond. res.

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We have studied crystal structure and associated defects in GaN films grown on sapphire under nitrogen-deficient conditions by metalorganic chemical vapor deposition (MOCVD) and pulsed laser deposition (PLD). The structural quality of the PLD films grown at 750 0 C was comparable with those grown by MOCVD at 1050 0 C having threading dislocations density of about 10 10 cm -2 at a film thickness 150-200 nm. Microstructure of the PLD films grown at temperatures above 780 0 C was found to be similar to that of nitrogen-deficient MOCVD films indicating the loss of nitrogen due to thermal decomposition of the nitride layers. Nitrogen-deficient MOCVD and PLD films exhibit polycrystalline structure with a mixture of cubic zinc-blende and wurtzite hexagonal GaN grains retaining tetragonal bonding across the boundaries and hence the epitaxial orientations and polarity. Renucleation of the wurtzite phase at different {111} planes of cubic GaN results in a rough and faceted surface of the film. Most of the stoichiometric films displayed (0001) Ga-face polarity, but the renucleated inclined wurtzite grains grew in the opposite N-face polarity. The major defects related to the cubic structural metastability are stacking faults and microtwins which being nuclei of the metastable cubic phase have an extremely low energy. We elucidate that the cubic phase is more stable under the nitrogen deficiency and, therefore, can exist without decomposition at higher nitrogen vacancy concentrations in the material.

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In situ control of gan growth by molecular beam epitaxy

Cited by 74 publications

References 10 publications

Reconstructions of GaN and InGaN surfaces

Reconstructions of GaN and InGaN surfaces

The role of gaseous species in group-III nitride growth

CRYSTAL STRUCTURE AND DEFECTS IN NITROGEN-DEFICIENT GaN

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