Diffusion of ion-implanted boron impurities into pre-amorphized silicon

Ohno, N.; Hara, Tohru; Matsunaga, Y.; Current, Michael; Inoue, M.

doi:10.1016/s1369-8001(00)00036-6

Cited by 9 publications

(8 citation statements)

References 8 publications

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“…In addition, B + ions were implanted in strained Si/strained Si 0.5 Ge 0.5 /SSOI heterostructures implanted (amorphized) before with Si + ions, (Si + +B + ), a method previously used for USJ formation in pure Si and Ge. 21 The implantation parameters were selected based on SILVACO simulations, by computing molecular implants of BF 2 + . We have selected implantation energies of 1.5 keV and 6 keV, corresponding to a common mean H45 projected ion range, R p , of 8.5 nm for both B + and BF 2 + .…”

Section: Methodsmentioning

confidence: 99%

p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures

Minamisawa

Buca

Holländer

et al. 2011

J. Electrochem. Soc.

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We present a systematic study on the formation of p-type doped strained Si / strained SiGe heterostructures by B + , BF + 2 and (Si + +B + ) ion implantation and annealing at moderate temperatures. The aim of this paper is to address the challenge of conserving the elastic strain during dopant activation. The most important result is that efficient doping combined with the conservation of strain and a good crystalline quality can only be obtained for BF 2 + implants with 1×10 15 ions/cm 2 and anneals at 650 • C. With these parameters, single crystalline layers with negligible strain relaxation and a sheet resistance of 886 /sq were achieved. The implantation of B + requires higher doses to reach low sheet resistances resulting in low layer quality and higher strain relaxation. Si + pre-implantation yields the lowest sheet resistances, but on the expense of strain (relaxation values over 60%). Finally, the optimized ion implantation / anneal parameters were applied for strained SiGe quantum-well MOSFETs with GdScO 3 high-κ gate dielectric.

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Section: Methodsmentioning

confidence: 99%

p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures

Minamisawa

Buca

Holländer

et al. 2011

J. Electrochem. Soc.

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“…Additionally, the use of ion beams to purposely pre-amorphize semiconductors is preferred in order to better control the spatial distribution of the implanted dopants. Indeed, when ion implantation is performed on a crystalline material, the dopant profile is more difficult to predict due to effects such as ion channelling [20]. In fact, it has been shown that using a pre-amorphized semiconductor before performing ion beam doping ultimately leads to better performance of the processed semiconductor after annealing [21].…”

Section: Introductionmentioning

confidence: 99%

Anomalous nucleation of crystals within amorphous germanium nanowires during thermal annealing

et al. 2021

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In this work, germanium nanowires rendered fully amorphous via xenon ion irradiation have been annealed within a transmission electron microscope to induce crystallization. During annealing crystallites appeared in some nanowires whilst others remained fully amorphous. Remarkably, even when nucleation occurred, large sections of the nanowires remained amorphous even though the few crystallites embedded in the amorphous phase were formed at a minimum of 200°C above the temperature for epitaxial growth and 100°C above the temperature for random nucleation and growth in bulk germanium. Furthermore, the presence of crystallites was observed to depend on the diameter of the nanowire. Indeed, the formation of crystallites occurred at a higher annealing temperature in thin nanowires compared with thicker ones. Additionally, nanowires with a diameter above 55 nm were made entirely crystalline when the annealing was performed at the temperature normally required for crystallization in germanium (i.e. 500°C). It is proposed that oxygen atoms hinder both the formation and the growth of crystallites. Furthermore, as crystallites must reach a minimum size to survive and grow within the amorphous nanowires, the instability of crystallites may also play a limited role for the thinnest nanowires.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This research has been motivated by the requirement in advanced CMOS technologies to minimize boron diffusion for the formation of shallow source/drain junctions and sharply defined halo profiles. 19,20 The minimization of boron diffusion is also important in bipolar transistors, where boron diffusion limits the achievable base width and hence the value of cutoff frequency that can be obtained.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] A chemical interaction between boron and fluorine has been proposed to explain the suppression of boron transient enhanced diffusion by fluorine, 4,9,11,14,16 in which the fluorine combines with interstitial boron reducing its mobility 4,11,14,16 or reduces the probability of formation of a boron interstitial pair. 9,11 Alternatively, the formation of vacancy-fluorine complexes has been proposed, 13,17,18,[23][24][25][26] which act as a barrier for boron diffusion, 13 or suppress the interstitial concentration and hence reduce boron transient enhanced diffusion 17 and thermal diffusion.…”

Section: Introductionmentioning

confidence: 99%

Effect of fluorine implantation dose on boron thermal diffusion in silicon

Mubarek

Bonar

Dilliway

et al. 2004

Journal of Applied Physics

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This paper investigates how the thermal diffusion of boron in silicon is influenced by a high energy fluorine implant with a dose in the range 5 ϫ 10 14 -2.3ϫ 10 15 cm −2 . Secondary Ion Mass Spectroscopy (SIMS) profiles of boron marker layers are presented for different fluorine doses and compared with fluorine profiles to establish the conditions under which thermal boron diffusion is suppressed. The (SIMS) profiles show significantly reduced boron thermal diffusion above a critical F + dose of 0.9-1.4ϫ 10 15 cm −2 . Fitting of the measured boron profiles gives suppressions of the boron thermal diffusion coefficient by factors of 1.9 and 3.7 for F + implantation doses of 1.4 ϫ 10 15 and 2.3ϫ 10 15 cm −2 , respectively. The suppression of boron thermal diffusion above the critical fluorine dose correlates with the appearance of a shallow fluorine peak on the (SIMS) profile in the vicinity of the boron marker layer. This shallow fluorine peak is present in samples with and without boron marker layers, and hence it is not due to a chemical interaction between the boron and the fluorine. Analysis of the (SIMS) profiles and cross-section Transmission Electron Microscope micrographs suggests that it is due to the trapping of fluorine at vacancy-fluorine clusters, and that the suppression of the boron thermal diffusion is due to the effect of the clusters in suppressing the interstitial concentration in the vicinity of the boron profile.

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Diffusion of ion-implanted boron impurities into pre-amorphized silicon

Cited by 9 publications

References 8 publications

p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures

p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures

Anomalous nucleation of crystals within amorphous germanium nanowires during thermal annealing

Effect of fluorine implantation dose on boron thermal diffusion in silicon

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Diffusion of ion-implanted boron impurities into pre-amorphized silicon

Cited by 9 publications

References 8 publications

p-Type Ion Implantation in Tensile Si/Compressive Si0.5Ge0.5/Tensile Strained Si Heterostructures

p-Type Ion Implantation in Tensile Si/Compressive Si0.5Ge0.5/Tensile Strained Si Heterostructures

Anomalous nucleation of crystals within amorphous germanium nanowires during thermal annealing

Effect of fluorine implantation dose on boron thermal diffusion in silicon

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Product

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p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures

p-Type Ion Implantation in Tensile Si/Compressive Si_0.5Ge_0.5/Tensile Strained Si Heterostructures