Dislocation density reduction through annihilation in lattice-mismatched semiconductors grown by molecular-beam epitaxy

Sheldon, P.; Jones, K. M.; Al‐Jassim, Mowafak; Yacobi, B. G.

doi:10.1063/1.340343

Cited by 81 publications

(43 citation statements)

References 8 publications

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“…For the directly grown samples (a) and (b), we observe that D is inversely proportional to x. This is explained by the pairannihilation mechanism of TDs and consistent with previous reliable reports [8][9][10]. The behavior of D dominated by the pair-annihilation mechanism is described by a differential equation…”

Section: Methodssupporting

confidence: 83%

“…In fact, for InGa(Al)As with indium contents less than $0.5, the graded-buffer growth is effective to reduce the near-surface threading dislocation (TD) density in comparison with the direct growth. A TD density less than $10 8 cm À2 can be obtained by the graded buffers of $1.0 mm thickness [6], while the direct growth gives $10 9 cm À2 for $1.0 mm thickness [8]. However, the fundamental mechanism of the reduction of the TD density by the graded buffers is not quite clear.…”

Section: Introductionmentioning

confidence: 95%

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Invalidity of graded buffers for InAs grown on GaAs (001)—A comparison between direct and graded-buffer growth

Jeong

Choi

Suzuki

2007

Journal of Crystal Growth

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Section: Methodssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 95%

Invalidity of graded buffers for InAs grown on GaAs (001)—A comparison between direct and graded-buffer growth

Jeong

Choi

Suzuki

2007

Journal of Crystal Growth

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“…!in thti&fless. ZZ7 reduction has also been reported for InAs/GaAs, GaAs/Ge/Si, GaAs/InP, and InAsfinP by Sheldon et al [3], showing similar l/h dependence for all 4 material systems. They found TD density to be inversely proportional to film thickness for initial TD densities of 108-109 cm-*.…”

Section: Introductionsupporting

confidence: 50%

Annihilation Radii for Dislocations Intercepting a Free Surface with Application to Heteroepitaxial Thin Film Growth

et al. 1998

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One critical issue in heteroepitaxial, lattice mismatched growth is the inevitable appearance of threading dislocations which reside in the relaxing film and degrade its semiconducting properties. It has been shown in previous work that threading dislocations interact with each other through a series of annihilation and fusion reactions to decrease their density as the film thickness increases and follow a l/h decay, where h is the film thickness. A characteristic reaction radius is associated with these interactions. In previous simulations, the reaction radius was taken to be a constant value estimated using a simple approximation based on infinite, parallel dislocation lines. Here, a continuum-based elasticity approach is taken to more accurately quantify the reaction radius by comparing the Peach-Koehler force of one dislocation acting on another at a free surface with the lattice resistance to dislocation motion. The presence of the free surface gives rise to a moderate reduction of the interaction force. Results are compared with preliminary experimental data for GaAs films grown on InP. INTRODUCTION AND BACKGROUND

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“…The authors used this model successfully to explain the 1/h -scaling behavior observed experimentally in several cubic materials by Sheldon et al 38 We applied this model to our experimental data from HVPE GaN layers presented in Fig. 5.…”

Section: Extended Defects Misfit Dislocationsmentioning

confidence: 99%

Extended defects and polarity of hydride vapor phase epitaxy GaN

Jasiński

Liliental‐Weber

2002

Journal of Elec Materi

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Hydride vapor phase epitaxy (HVPE) GaN layers on sapphire substrates and so-called free-standing platelets (layers removed from the sapphire)were studied by different transmission electron microscopy (TEM) techniques. Polarity determined by convergent beam electron diffraction (CBED) and distribution of structural defects, determined by conventional TEM, are discussed. HVPE layers were found to grow primarily with Gapolarity. A few inversion domains (areas with N-polarity) were observed on the substrate side of one of the free-standing layers. The dominant structural defects in HVPE GaN layers are threading dislocations. A systematic reduction of their density with increase in layer thickness was observed for all samples. The experimental results indicate that the density of dislocations is inversely proportional to the distance from the substrate, which agrees with the theoretical model. INTRODUCTIONIn recent years, GaN-based semiconductors have attracted scientific interest because of their importance in many applications, mostly in optoelectronic, and highpower, and high-temperature electronic devices. Good quality GaN-based light-emitting diodes, blue lasers and metal-semiconductor field-effect transistors have been demonstrated. [1][2][3][4][5][6] Despite the large number of applications and wide spread interest in GaN and other III-nitrides there are still some problems associated with the technology of these materials. One of them is the problem with available substrates for epitaxial growth of nitride semiconductor layers. There are still some difficulties in growing large bulk Advanced Institute of Technology. The last two samples (they will be referred to later in this paper as samples: FS1 and FS2) were also grown on a sapphire substrate and their initial thickness before laser induced lift off 25 was about 300 µm. After separation from the substrate these layers were mechanically polished, and dry etched on their original surface to obtain a smooth epi-ready surface. The opposite surface was only mechanochemically polished. For these two layers TEM plan-view specimens were prepared from both sides and from the remaining ones with the exception of the sample with the thickness of 55 µm where the large accumulated stress caused constant breaking only from the surface side. All TEM specimens were prepared by a standard method of mechanical pre-thinning followed by Ar-ion milling down to electron transparency. TEM 4 studies were carried out using a TOPCON 002B microscope, operated at 200 kV acceleration voltage. RESULTS AND DISCUSSION CRYSTAL POLARITYThe [0001] direction of the GaN layer grown on a c-plane sapphire substrate can have two different polarities. These polarities correspond to orientation of the Ga-N bond, which is parallel to the c-axis. A layer has a Ga-polarity when the growth direction points from the Ga atom towards the N atom. When the growth direction points from the N atom towards the Ga atom a layer has a N-polarity.In order to determine the polarity of the investigated GaN layers ...

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Dislocation density reduction through annihilation in lattice-mismatched semiconductors grown by molecular-beam epitaxy

Cited by 81 publications

References 8 publications

Invalidity of graded buffers for InAs grown on GaAs (001)—A comparison between direct and graded-buffer growth

Invalidity of graded buffers for InAs grown on GaAs (001)—A comparison between direct and graded-buffer growth

Annihilation Radii for Dislocations Intercepting a Free Surface with Application to Heteroepitaxial Thin Film Growth

Extended defects and polarity of hydride vapor phase epitaxy GaN

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