Characteristics of dislocations at strained heteroepitaxial InGaAs/GaAs interfaces

Chang, Kai; Bhattacharya, P.; Gíbala, R.

doi:10.1063/1.344183

Cited by 125 publications

(29 citation statements)

References 29 publications

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“…Formation of edge MDs based on random meeting of two parallel-propagating 60 MDs (mechanism A) was discussed in several publications 16,18,25 as a most reasonable model explaining the emergence of edge MDs in strained GeSi and InGaAs films epitaxially grown on Si(001) and GaAs substrates. This mechanism of edge MD formation is likely operating in films that were grown with a considerable amount of lattice imperfections, for the most part, 60 MDs, and were subsequently given a thermal anneal (see, for instance, Ref.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of edge-dislocation formation in strained films of zinc blende and diamond cubic semiconductors epitaxially grown on (001)-oriented substrates

Bolkhovityanov

Deryabin

Гутаковский

et al. 2011

Journal of Applied Physics

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Ninety degree edge misfit dislocations (MDs) are «sessile» dislocations; such dislocations, however, were found in large amounts in relaxed films. The commonly accepted formation mechanism of such dislocations is an interaction of two complementary 60° dislocations with appropriate Burger’s vectors, for example: a/2[101−] + a/2 [011] = a/2 [110]. In the present study, four possible types of interaction were analyzed: (i) random meeting of two complementary MDs; (ii) crossing of two complementary 60° MDs in the vicinity of film-substrate interface in systems grown on substrates misoriented from exact (001) orientation; (iii) formation of edge MDs during cross-slipping of a secondary MD; and (iv) induced nucleation of a secondary complementary 60° MD. Examples of discussed interactions are given. Contrary to the widespread opinion that edge MDs in GeSi and InGaAs films grown by MBE on Si and GaAs substrates predominantly form under elastic strains greater than 2% and at the final stage of plastic relaxation, in the present study, we show that such dislocations may also form at an early stage of plastic relaxation in films with less-than-1% lattice misfit with substrate. A necessary condition for that is a sufficient amount of 60° dislocations available in the system by the moment the strained film starts growing. Dislocations (60°) can be introduced into the system using a preliminarily grown, partially or fully relaxed buffer layer. This layer serves as a source of threading dislocations for the next growing layer that favor the formation of paired complementary MDs and their «reagents», edge MDs, at the interface with growing film.

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Section: Discussionmentioning

confidence: 99%

Mechanisms of edge-dislocation formation in strained films of zinc blende and diamond cubic semiconductors epitaxially grown on (001)-oriented substrates

Bolkhovityanov

Deryabin

Гутаковский

et al. 2011

Journal of Applied Physics

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“…According to Matthews and Blakeslee [29,30], the MD is actually closely associated with TD, i.e., TD would glide laterally to leave behind a length l of 60° MD segment nearly parallel to the interface for accommodating the elastic strain. In the present case, it has been verified in the experiments that the dominant type of MD is the orthogonal arrays of 60° dislocations lying along two different 〈110〉 crystallographic directions and gliding on a {111} plane [30][31][32]. Such physical image is depicted in Figure 6, where the TD segments, indicated by a horizontal arrow, leave behind a length l of 60° MD segment nearly parallel to the interface, and they can be linked together through geometry relation [29,30]:…”

Section: Resultsmentioning

confidence: 83%

Evaluating the effect of dislocation on the photovoltaic performance of metamorphic tandem solar cells

Zhang

Chen

Wang

et al. 2010

Sci. China Technol. Sci.

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The photovoltaic conversion efficiency for monolithic GaInP/GaInAs/Ge triple-junction cell with various bandgap combination (300 suns, AM1.5d) was theoretically calculated. An impressive improvement on conversion efficiency was observed for a bandgap combination of 1.708, 1.194, and 0.67 eV. A theoretical investigation was carried out on the effect of dislocation on the metamorphic structure's efficiency by regarding dislocation as minority-carrier recombination center. The results showed that only when dislocation density was less than 1.6×10 6 cm −2 , can this metamorphic combination exhibit its efficiency advantage over the fully-matched combination. In addition, we also briefly evaluated the lattice misfit dependence of the dislocation density for a group of metamorphic triple-junction system, and used it as guidance for the choice of the proper cell structure. tandem solar cell, theoretical efficiency, dislocation, buffer layers Citation: Zhang H, Chen N F, Wang Y, et al. Evaluating the effect of dislocation on the photovoltaic performance of metamorphic tandem solar cells. Sci

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“…10,30,31 Such reactions are favored since there is a large reduction in strain energy involved ͑b 2 criterion͒. However, the edge dislocations, lying in the ͑001͒ planes are sessile and can only react through a climb process.…”

Section: Dislocation Structurementioning

confidence: 99%

Novel dislocation structure and surface morphology effects in relaxed Ge/Si-Ge(graded)/Si structures

Samavedam

Fitzgerald

1997

Journal of Applied Physics

186

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The defect structure in relaxed graded Ge/Ge x Si 1Ϫx /Si structures grown on ͑001͒ exact and ͑001͒ off-cut substrates using ultra-high vacuum chemical vapor deposition was characterized using transmission electron microscopy ͑TEM͒, atomic force microscopy, and electron beam induced current. The samples grown on off-cut ͑001͒ substrates showed a remarkable improvement in surface roughness and dislocation pile-up densities. By applying both a dislocation blocking criterion and surface roughness to graded Si-Ge/Si͑001͒ structures, we can predict the formation of dislocation pile-ups in graded structures. Nonparallel misfit dislocation networks in off-cut wafer samples are not as efficient at blocking perpendicular dislocation motion, leading to a large reduction in dislocation pile-up density. The lower pile-up density on layers grown on off-cut wafers results in less stress-induced surface instability during growth, leading to surfaces with much lower roughness. TEM studies revealed that the array of 60°dislocations, that usually forms to relieve the misfit stress, transforms into a lower energy hexagonal dislocation network consisting of edge dislocations with Burgers vectors of the type 1/2͗110͘, 1/2͗110͘, and ͗100͘. Such reactions were found to be more prevalent in the samples grown on off-cut substrates. Favorable intersections of ͕111͖ type planes on the off-cut substrates were found to aid such reactions.

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Characteristics of dislocations at strained heteroepitaxial InGaAs/GaAs interfaces

Cited by 125 publications

References 29 publications

Mechanisms of edge-dislocation formation in strained films of zinc blende and diamond cubic semiconductors epitaxially grown on (001)-oriented substrates

Mechanisms of edge-dislocation formation in strained films of zinc blende and diamond cubic semiconductors epitaxially grown on (001)-oriented substrates

Evaluating the effect of dislocation on the photovoltaic performance of metamorphic tandem solar cells

Novel dislocation structure and surface morphology effects in relaxed Ge/Si-Ge(graded)/Si structures

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