Rapid annealing and the anomalous diffusion of ion implanted boron into silicon

Michel, A. E.; Rausch, W.; Ronsheim, P.; Kastl, R. H.

doi:10.1063/1.98160

Cited by 213 publications

(74 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 5͑b͒ shows that the enhanced boron diffusion is primarily seen in the 0 -15 s time period, which implies that majority of the TED occurs in the first 15 s of the anneal. This conclusion is consistent with the results of a study by Michel et al, 22 who showed that boron TED ends after ϳ15 s at 950°C.…”

Section: Discussionsupporting

confidence: 83%

Reduced boron diffusion under interstitial injection in fluorine implanted silicon

Kham

Maťko

Chenevier

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

Point defect injection studies are performed to investigate how fluorine implantation influences the diffusion of boron marker layers in both the vacancy-rich and interstitial-rich regions of the fluorine damage profile. A 185 keV, 2.3ϫ 10 15 cm −2 F + implant is made into silicon samples containing multiple boron marker layers and rapid thermal annealing is performed at 1000°C for times of 15-120 s. The boron and fluorine profiles are characterized by secondary ion mass spectroscopy and the defect structures by transmission electron microscopy ͑TEM͒. Fluorine implanted samples surprisingly show less boron diffusion under interstitial injection than those under inert anneal. This effect is particularly noticeable for boron marker layers located in the interstitial-rich region of the fluorine damage profile and for short anneal times ͑15 s͒. TEM images show a band of dislocation loops around the range of the fluorine implant and the density of dislocation loops is lower under interstitial injection than under inert anneal. It is proposed that interstitial injection accelerates the evolution of interstitial defects into dislocation loops, thereby giving transient enhanced boron diffusion over a shorter period of time. The effect of the fluorine implant on boron diffusion is found to be the opposite for boron marker layers in the interstitial-rich and vacancy-rich regions of the fluorine damage profile. For marker layers in the interstitial-rich region of the fluorine damage profile, the boron diffusion coefficient decreases with anneal time, as is typically seen for transient enhanced diffusion. The boron diffusion under interstitial injection is enhanced by the fluorine implant at short anneal times but suppressed at longer anneal times. It is proposed that this behavior is due to trapping of interstitials at the dislocation loops introduced by the fluorine implant. For boron marker layers in the vacancy-rich region of the fluorine damage profile, suppression of boron diffusion is seen for short anneals and then increased diffusion after a critical time, which is longer for inert anneal than interstitial injection. This behavior is explained by the annealing of vacancy-fluorine clusters, which anneal quicker under interstitial injection because the injected interstitials annihilate vacancies in the clusters.

show abstract

Section: Discussionsupporting

confidence: 83%

Reduced boron diffusion under interstitial injection in fluorine implanted silicon

Kham

Maťko

Chenevier

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The Is excess increases the B diffusivity, as shown since 1973 with an enhanced diffusion of B atoms implanted in Si. 60,61 Such a non-equilibrium phenomenon revealed a transitory feature, lasting for about 45 min at 800 C and some seconds at 1000 C, 62 deserving the name of transient enhanced diffusion (TED). The cause of this effect was discovered in mid nineties 63,64 and clearly attributed to the simultaneous thermal dissolution of {311} defects (extended rod-like I clusters displaced on {311} habit planes) formed as a consequence of the coalescence of the implant damage.…”

Section: A Milestones On the B Diffusion Mechanismmentioning

confidence: 99%

“…[60][61][62]72 In the following, a concise selection of the numerous papers dedicated to this phenomenon will be presented, with the aim to elucidate the main issues which could affect the B diffusion.…”

Section: B-i Clusters Formation and Dissolutionmentioning

confidence: 99%

Mechanisms of boron diffusion in silicon and germanium

Mirabella

Salvador

Napolitani

et al. 2013

Journal of Applied Physics

103

View full text Add to dashboard Cite

B migration in Si and Ge matrices raised a vast attention because of its inﬂuence on the production of conﬁned, highly p-doped regions, as required by the miniaturization trend. In this scenario, the diffusion of B atoms can take place under severe conditions, often concomitant, such as very large concentration gradients, non-equilibrium point defect density, amorphous-crystalline transition, extrinsic doping level, co-doping, B clusters formation and dissolution, ultra-short high-temperature annealing. In this paper, we review a large amount of experimental work and present our current understanding of the B diffusion mechanism, disentangling concomitant effects and describing the underlying physics. Whatever the matrix, B migration in amorphous (a-) or crystalline (c-) Si, or c-Ge is revealed to be an indirect process, activated by point defects of the hosting medium. In a-Si in the 450-650 C range, B diffusivity is 5 orders of magnitude higher than in c-Si, with a transient longer than the typical amorphous relaxation time. A quick B precipitation is also evidenced for concentrations larger than 2 x10^20 B/cm3. B migration in a-Si occurs with the creation of a metastable mobile B, jumping between adjacent sites, stimulated by dangling bonds of a-Si whose density is enhanced by B itself (larger B density causes higher B diffusivity). Similar activation energies for migration of B atoms (3.0 eV) and of dangling bonds (2.6 eV) have been extracted. In c-Si, B diffusion is largely affected by the Fermi level position, occurring through the interaction between the negatively charged substitutional B and a self-interstitial (I) in the neutral or doubly positively charged state, if under intrinsic or extrinsic (p-type doping) conditions, respectively. After charge exchanges, the migrating, uncharged BI pair is formed. Under high n-type doping conditions, B diffusion occurs also through the negatively charged BI pair, even if the migration is depressed by Coulomb pairing with n-type dopants. The interplay between B clustering and migration is also modeled, since B diffusion is greatly affected by precipitation. Small (below 1 nm) and relatively large (5-10 nm in size) BI clusters have been identiﬁed with different energy barriers for thermal dissolution (3.6 or 4.8 eV, respectively). In c-Ge, B motion is by far less evident than in c-Si, even if the migration mechanism is revealed to be similarly assisted by Is. If Is density is increased well above the equilibrium (as during ion irradiation), B diffusion occurs up to quite large extents and also at relatively low temperatures, disclosing the underlying mechanism. The lower B diffusivity and the larger activation barrier (4.65 eV, rather than 3.45 eV in c-Si) can be explained by the intrinsic shortage of Is in Ge and by their large formation energy. B diffusion can be strongly enhanced with a proper point defect engineering, as achieved with embedded GeO2 nanoclusters, causing at 650 °C a large Is supersaturation. These aspects of B diffusion are presented and discus...

show abstract

“…A similar form applies for dissociation rates from clusters, with E, replaced by a dissociation energy that includes the binding energy, E,, of a particle to the cluster. Specifically, the effective diffusivity for a free particle leaving a cluster is taken as D = Do exp[-(E,+E,)/kT], (2) because the particle must migrate one jump distance away from the cluster to be free. The BIGMAC program requires input tables of Do and E,,, for all mobile species, as well as the prefactors and binding energies for all possible clusters.…”

Section: Kinetic Monte Carlo Simulationmentioning

confidence: 99%

Atomic scale models of ion implantation and dopant diffusion in silicon

et al. 2000

View full text Add to dashboard Cite

We review our recent work on an atomistic approach to the development of predictive process simulation tools. First principles methods, molecular dynamics simulations, and experimental results are used to construct a database of defect and dopant energetics in Si. This is used as input for kinetic Monte Carlo simulations. C and B trapping of the Si selfinterstitial is shown to help explain the enormous disparity in its measured diffusivity.Excellent agreement is found between experiments and simulations of transient enhanced diffusion following 20-80 keV B implants into Si, and with those of 50 keV Si implants into complex B-doped structures. Our simulations predict novel behavior of the time evolution of the electrically active B fraction during annealing.

show abstract

Rapid annealing and the anomalous diffusion of ion implanted boron into silicon

Cited by 213 publications

References 11 publications

Reduced boron diffusion under interstitial injection in fluorine implanted silicon

Reduced boron diffusion under interstitial injection in fluorine implanted silicon

Mechanisms of boron diffusion in silicon and germanium

Atomic scale models of ion implantation and dopant diffusion in silicon

Contact Info

Product

Resources

About