Activation energy for fluorine transport in amorphous silicon

Nash, George; Schiz, J.; Marsh, C.D.; Ashburn, P.; Booker, G. R.

doi:10.1063/1.125424

Cited by 20 publications

(15 citation statements)

References 19 publications

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“…10͑a͔͒. Both of them are very similar to the F diffusion coefficient reported by Nash et al 18 The other diffusion-related parameters ͓͑T͔ bulk and ͒ do not strongly depend on temperature but they seem to depend on the intrinsic properties of the amorphous phase. The background trap density is ϳ10 20 at/ cm 3 ͑see Table II͒, suggesting that these traps might be amorphous bulk defects, whose density in relaxed amorphous Si is known to be at most 1% at.…”

Section: Resultssupporting

confidence: 87%

“…The fact that the two different quantities coincide with each other can be understood within the framework of the present model by considering that the a-Si used in Ref. 18 has been produced by deposition, that is a considerably different method with respect to the one used for our samples. Their material might therefore contain traps for mobile F at concentrations low enough for not having any significant influence on the F diffusion.…”

Section: Resultsmentioning

confidence: 91%

“…18͒ but the microscopic mechanism driving F diffusion in a-Si is still unclear. Nash et al 18 also observed immobile F in the vicinity of the F implant peak in a-Si and they suggested that some F is trapped at damage associated with ion implantation.…”

Section: Introductionmentioning

confidence: 97%

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Fluorine redistribution and incorporation during solid phase epitaxy of preamorphized Si

et al. 2010

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The redistribution of fluorine during solid phase epitaxial regrowth (SPER) of preamorphized Si has been experimentally investigated, explained, and simulated, for different F concentrations and temperatures. We demonstrate, by a detailed analysis and modeling of F secondary ion mass spectrometry chemical-concentration profiles, that F segregates in amorphous Si during SPER by splitting in three possible states: (i) a diffusive one that migrates in amorphous Si; (ii) an interface segregated state evidenced by the presence of a F accumulation peak at the amorphous-crystal interface; (iii) a clustered F state. The interplay among these states and their roles in the F incorporation into crystalline Si are fully described. It is shown that diffusive F migrates by a trap limited diffusion mechanism and also interacts with the advancing interface by a sticking-release dynamics that regulates the amount of F segregated at the interface. We demonstrate that this last quantity determines the regrowth rate through an exponential law. On the other hand we show that neither the diffusive F nor the one segregated at the interface can directly incorporate into the crystal but F has to cluster in the amorphous phase before being incorporated in the crystal, in agreement with recent experimental observations. The trends of the model parameters as a function of the temperature are shown and discussed obtaining a clear energetic scheme of the F redistribution and incorporation in preamorphized Si. The above physical understanding and the model could have a strong impact on the use of F as a tool for optimizing the doping profiles in the fabrication of ultrashallow junctions

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 91%

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Fluorine redistribution and incorporation during solid phase epitaxy of preamorphized Si

et al. 2010

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“…The only experiment realized in amorphous Si ͑a-Si͒ has been conducted by Nash et al, who studied the transport of F using secondary ion mass spectrometry ͑SIMS͒ and showed by TEM that F transport is influenced by F "inclusions." 12 Clearly, it is now necessary to study the generation of F bubbles in detail and to investigate their possible formation starting from the amorphous phase.…”

Section: Formation and Evolution Of F Nanobubbles In Amorphous And Crmentioning

confidence: 99%

Formation and evolution of F nanobubbles in amorphous and crystalline Si

Boninelli

Impellizzeri

Mirabella

et al. 2008

Applied Physics Letters

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The formation and evolution of F-induced nanobubbles in Si was investigated. Si samples were preamorphized, implanted with F, and partially regrown by solid phase epitaxy (SPE). It is shown that nanobubbles are formed already in the amorphous side of partially regrown samples and are then incorporated in crystalline Si during SPE. The bubbles are interpreted as the result of the diffusion and coalescence of F atoms and dangling bonds already in the amorphous matrix. During high temperature annealing after SPE, F outdiffuses; correspondingly, the bubbles partially dissolve and transform from spherical- to cylinder-shaped bubbles. (C) 2008 American Institute of Physics

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“…No values have yet been reported for the diffusion of fluorine in either singlecrystal silicon or polysilicon and the diffusion mechanisms are uncertain. Nash et al 22 showed that the diffusivities of fluorine in amorphous silicon in the range of 600-700°C were in the range 4.5-47ϫ10 Ϫ14 cm 2 s Ϫ1 respectively.…”

Section: Introductionmentioning

confidence: 99%

Behavior and effects of fluorine in annealed n+ polycrystalline silicon layers on silicon wafers

Marsh

Moiseiwitsch

Booker

et al. 2000

Journal of Applied Physics

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A comprehensive study is made of the behavior and effects of fluorine in n ϩ -polysilicon layers. The polysilicon is deposited in a conventional low pressure chemical vapor deposition furnace on ͑100͒ silicon wafers, implanted with 1ϫ10 16 cm Ϫ2 F ϩ and 1ϫ10 16 cm Ϫ2 As ϩ and annealed at 850, 950, 1015, and 1065°C. Sheet resistance, transmission electron microscopy ͑TEM͒, and secondary ion mass spectroscopy are used to obtain quantitative data for the breakup of the interfacial oxide, the epitaxial regrowth of the polysilicon layer, and the fluorine and arsenic distributions. The fluorine significantly increases both the initial oxide breakup ͑ϳ8ϫ͒ and the initial polysilicon regrowth. It also produces inclusions in the layer which can affect the subsequent polysilicon regrowth and the arsenic distributions. Three regrowth stages and two regrowth mechanisms are distinguished and interpreted, and a value of ϳ6ϫ10 Ϫ11 cm 2 s Ϫ1 is deduced for the effective diffusivity of fluorine in polysilicon at 950°C. The amounts of regrowth determined by TEM are compared with the corresponding changes in sheet resistance. The thermal budgets required to produce polysilicon layer regrowths of 1% and 50%, important for the performance of polysilicon emitter bipolar transistors, are given. All the thermal budgets are lower when fluorine is present.

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Activation energy for fluorine transport in amorphous silicon

Cited by 20 publications

References 19 publications

Fluorine redistribution and incorporation during solid phase epitaxy of preamorphized Si

Fluorine redistribution and incorporation during solid phase epitaxy of preamorphized Si

Formation and evolution of F nanobubbles in amorphous and crystalline Si

Behavior and effects of fluorine in annealed n+ polycrystalline silicon layers on silicon wafers

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