Ultrashallow profiling using secondary ion mass spectrometry: Estimating junction depth error using mathematical deconvolution

Yang, Manman; Mount, Gary; Mowat, Ian A.

doi:10.1116/1.2132319

Cited by 13 publications

(5 citation statements)

References 10 publications

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“…This is consistent with surface manganese oxide, in agreement with other reports [16] and the broad UV-vis peak below 500 nm (figure 1) [19]. Therefore, to avoid introduction of Mn due to beam-induced mixing [20], and to focus on the Mn that has been incorporated into Si exclusively by the UV process, the UV-irradiated samples were Pirhana cleaned to remove any Mn-rich surface contaminants. Figure 2(a) shows a sample that has been UV-treated and subjected to a Piranha clean.…”

supporting

confidence: 90%

A novel route for the inclusion of metal dopants in silicon

Gardener¹,

Liaw²,

Aeppli³

et al. 2009

Nanotechnology

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We report a new method for introducing metal atoms into silicon wafers, using negligible thermal budget. Molecular thin films are irradiated with ultra-violet light releasing metal species into the semiconductor substrate. Secondary ion mass spectrometry and x-ray absorption spectroscopy show that Mn is incorporated into Si as an interstitial dopant. We propose that our method can form the basis of a generic low-cost, low-temperature technology that could lead to the creation of ordered dopant arrays.(Some figures in this article are in colour only in the electronic version) Chemically versatile, minimal thermal budget approaches to the controlled doping of semiconductor wafers become increasingly important as feature sizes fall. Subjecting pre-patterned dopant regions to high temperatures enhances diffusion and is detrimental to interface definition. Ion implantation or metallic thin film precursors can be used to dope semiconductors, but these procedures rely on annealing to produce high quality wafers [1,2]. Alternatively, growth methods such as molecular beam epitaxy (MBE) or metal organic chemical vapour deposition (MOCVD) can be utilized, although these are expensive and also require a high- temperature step [3][4][5]. Lateral control of dopant positioning can be achieved using scanning probe methods [6,7] or, recently, annealing of chemisorbed organic films [8]. However, these approaches are limited by a low prospect of upscaling and restrictive dopant-substrate combinations respectively. Here, we demonstrate a new approach, using clean, cheap vacuum ultra-violet (UV) sources [9] to degrade metalorganic thin films on Si at temperatures close to room temperature. This releases the metal atoms, which are subsequently incorporated into the substrate as dopants.The molecules chosen are phthalocyanines (MPc, figure 1 inset), which can form ordered films onto virtually any substrate [10]. Once deposited, these molecules remain intact, and so the ligands act to spatially separate the metal atoms. Important for the present application, MPcs can contain a vast range of species at their centre (most transition metals, rare earths, oxides, etc), and we envisage that the doping method demonstrated here for Mn in Si could be easily generalized to any dopant/substrate combination. Here, we focus on

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supporting

confidence: 90%

A novel route for the inclusion of metal dopants in silicon

Gardener¹,

Liaw²,

Aeppli³

et al. 2009

Nanotechnology

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“…The APT indicates As in the native oxide at a concentration of 3 × 10 20 /cm 3 , whereas SIMS analysis indicates 10 20 /cm 3 . APT provides equal collection efficiencies for atoms across the mass spectrum, whereas SIMS analysis at interfaces suffers from aberrations associated with variable sputter and ionization rates as a function of material type (28)(29)(30)(31). APT therefore provides a more accurate analysis than SIMS at the interface of dissimilar materials.…”

mentioning

confidence: 99%

Imaging of Arsenic Cottrell Atmospheres Around Silicon Defects by Three-Dimensional Atom Probe Tomography

Thompson

Flaitz

Ronsheim

et al. 2007

Science

178

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Discrete control of individual dopant or impurity atoms is critical to the electrical characteristics and fabrication of silicon nanodevices. The unavoidable introduction of defects into silicon during the implantation process may prevent the uniform distribution of dopant atoms. Cottrell atmospheres are one such nonuniformity and occur when interstitial atoms interact with dislocations, pinning the dislocation and trapping the interstitial. Atom probe tomography has been used to quantify the location and elemental identity of the atoms proximate to defects in silicon. We found that Cottrell atmospheres of arsenic atoms form around defects after ion implantation and annealing. Furthermore, these atmospheres persist in surrounding dislocation loops even after considerable thermal treatment. If not properly accommodated, these atmospheres create dopant fluctuations that ultimately limit the scalability of silicon devices.

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“…This sputter removal process mixes the top several nm of the exposed surface. Additionally, the energetic primary ion beam drives certain atomic species deeper into the sample, inhibiting the characterization of sharp composition gradients [15][16][17][18][19]. The result is an exaggeration of the transition between two layers or accumulation artefacts at this interface.…”

Section: Discussionmentioning

confidence: 99%

Compositional analysis of Si nanostructures: SIMS–3D tomographic atom probe comparison

Thompson

Bunton

Moore

et al. 2006

Semicond. Sci. Technol.

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3D atom probe tomography (APT) is introduced as a powerful compositional and spatial analytical tool for SiGe nanostructures. Compositional analysis of SiGe structures demonstrates that the location and identity of Si, Ge and B atoms can be detected in three dimensions. Superior sensitivity at Si-SiGe-Si interfaces is specifically witnessed by both the quantification of Ge accumulation at an interface (14% by atom probe versus 9% by SIMS) and a slope roll-off of ∼1 nm/decade for atom probe compared to ∼7 nm/decade for the corresponding SIMS analysis. Additionally, APT provides chemical roughness measurements of buried interfaces. In a specific case, a Si-SiGe-Si interface had a measured roughness of 0.47 nm at the Si-SiGe leading edge and 0.26 nm at the SiGe-Si trailing edge.

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Ultrashallow profiling using secondary ion mass spectrometry: Estimating junction depth error using mathematical deconvolution

Cited by 13 publications

References 10 publications

A novel route for the inclusion of metal dopants in silicon

A novel route for the inclusion of metal dopants in silicon

Imaging of Arsenic Cottrell Atmospheres Around Silicon Defects by Three-Dimensional Atom Probe Tomography

Compositional analysis of Si nanostructures: SIMS–3D tomographic atom probe comparison

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