Annealing of low-temperature GaAs studied using a variable energy positron beam

Keeble, D. J.; Umlor, M. T.; Asoka‐Kumar, P.; Lynn, K. G.; Cooke, P.

doi:10.1063/1.109706

Cited by 27 publications

(16 citation statements)

References 11 publications

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“…9,19 Positron annihilation results indicate the formation of defects larger than monovacancies during annealing. 10,11 It has been suggested that positron trapping in annealed LT-GaAs is related to As precipitates 20 whereas other authors interpreted their results in terms of isolated vacancy clusters. 10 The use of LT-GaAs for different applications requires a proper understanding of the defects which determine the properties of the material.…”

Section: Introductionmentioning

confidence: 77%

“…This is in accordance to the assumptions in the earlier PAS studies. [9][10][11]40,49 Due to the combination of different techniques in conjunction with theoretical calculations in the present study, the identification of V Ga can now be considered to be well established. Positron lifetime spectroscopy showed that the defects are monovacancies, whereas the conventional S -W analysis shows that they belong to the Ga sublattice.…”

Section: Discussionmentioning

confidence: 98%

“…It has been suggested that these defects are associated with As precipitates 20 but it has often been assumed that these are just isolated vacancy clusters. 10,11 In Fig. 7, the annihilation momentum distribution mea- sured in annealed LT-GaAs is compared with that of different reference samples.…”

Section: Positron Trapping At As-precipitates In Annealed Lt-gaasmentioning

confidence: 99%

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Defect identification in GaAs grown at low temperatures by positron annihilation

Gebauer¹,

Börner

Krause‐Rehberg

et al. 2000

Journal of Applied Physics

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We use positron annihilation to study vacancy defects in GaAs grown at low temperatures ͑LT-GaAs͒. The vacancies in as-grown LT-GaAs can be identified to be Ga monovacancies, V Ga , according to their positron lifetime and annihilation momentum distribution. The charge state of the vacancies is neutral. This is ascribed to the presence of positively charged As Ga ϩ antisite defects in vicinity to the vacancies. Theoretical calculations of the annihilation parameters show that this assignment is consistent with the data. The density of V Ga is related to the growth stoichiometry in LT-GaAs, i.e., it increases with the As/Ga beam equivalent pressure ͑BEP͒ and saturates at 2ϫ10 18 cm Ϫ3 for a BEPу20 and a low growth temperature of 200°C. Annealing at 600°C removes V Ga . Instead, larger vacancy agglomerates with a size of approximately four vacancies are found. It will be shown that these vacancy clusters are associated with the As precipitates formed during annealing.

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Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 98%

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Defect identification in GaAs grown at low temperatures by positron annihilation

Gebauer¹,

Börner

Krause‐Rehberg

et al. 2000

Journal of Applied Physics

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“…Thermal annealing experiments have been performed to elucidate vacancy formation mechanisms and the role of copper in determining the vacancy distribution in GaAs crystals (Elsayed et al, 2008(Elsayed et al, , 2011. LT-MBE GaAs is typically grown in conditions that favor the formation of Ga sublattice defects: Ga vacancies and As antisites (Bliss et al, 1992;Keeble et al, 1993;Störmer et al, 1996;Fleischer et al, 1997;Gebauer et al, 1997;Laine et al, 1999). The Ga vacancy-related defects follow the growth stoichiometry and compensate the n-type doping.…”

Section: Traditional Iii-v and Ii-vi Semiconductorsmentioning

confidence: 99%

Defect identification in semiconductors with positron annihilation: Experiment and theory

2013

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Positron annihilation spectroscopy is particularly suitable for studying vacancy-type defects in semiconductors. Combining state-of-the-art experimental and theoretical methods allows for detailed identification of the defects and their chemical surroundings. Also charge states and defect levels in the band gap are accessible. In this review the main experimental and theoretical analysis techniques are described. The usage of these methods is illustrated through examples in technologically important elemental and compound semiconductors. Future challenges include the analysis of noncrystalline materials and of transient defect-related phenomena.

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“…Different authors used models based on arsenic clusters and different point-defects. PAS measurements show a significant increase in vacancy concentration upon annealing [23,24]. The anneal-induced defect formation occurs concurrently with increases in resistivity and lattice relaxation.…”

Section: Applicationsmentioning

confidence: 92%

Studies of defects in the near-surface region and at interfaces using low energy positron beams

Asoka‐Kumar

1997

Bull Mater Sci

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Positron Annihilation Spectroscopy (PAS) is a powerful probe to study open-volume defects in solids. Its su'ccess is due to the propensity of positrons to seek out low-density regions of a solid, such as vacancies and voids, and the emissions of gamma rays from their annihilations that carry information about the local electronic environment. The development of low-energy positron beams allows probing of defects to depths of few microns, and can successfully characterize defects in the near-surface and interface regions of several technologically important systems. This review focuses on recent studies conducted on semiconductor-based systems. IntroductionThe last three decades saw an explosive growth in methods to produce materials with unique properties. Many of these techniques allowed the engineering of high-quality layered structures (both homo-and hetero-structures). Along with these advances, the need to characterize the defect content of these structures became evident. With many advanced materials, a single characterization method often is inadequate. Therefore, the material-research community has relied on a variety of techniques to control and optimize their processing steps. In this context, Positron Annihilation Spectroscopy (PAS) has become a powerful, nondestructive probe to characterize dilute quantities of open-volume defects.With the development of intense, variable-energy positron beams, it is possible now to examine defects in the near-surface regions and buried interfaces. Below, we describe the application of PAS to several advanced semiconductor-based systems, and include the following topics: defects in MBE-grown Si and GaAs, hydrogen interaction with Si dangling bonds, and electromigration-induced vacancy formation.

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Annealing of low-temperature GaAs studied using a variable energy positron beam

Abstract: Articles you may be interested inReduction of variable range hopping conduction in low-temperature molecular-beam epitaxy GaAs

Cited by 27 publications

References 11 publications

Defect identification in GaAs grown at low temperatures by positron annihilation

Defect identification in GaAs grown at low temperatures by positron annihilation

Defect identification in semiconductors with positron annihilation: Experiment and theory

Studies of defects in the near-surface region and at interfaces using low energy positron beams

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