Investigation of dopant clustering and segregation to defects in semiconductors using atom probe tomography

Blavette, D.; Duguay, S.

doi:10.1063/1.4948238

Cited by 11 publications

(10 citation statements)

References 25 publications

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“…We reasoned there is an alternate possibility: the dopants in the films may be heterogeneously distributed in the thin films as nanoscopic clusters similar to the nanoscopic charged regions in a contact electrified sample 47 . Dopant clusters have been observed in inorganic semiconductors 48 but are not commonly invoked in organic semiconductors as they are often doped in solution 49 . We then hypothesized that doping temperature alters the clustering of the dopants and thus the shape of the DOS, which in turn alters the relationship between the Seebeck coefficient and electrical conductivity.…”

Section: Resultsmentioning

confidence: 99%

Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films

et al. 2019

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A significant challenge in the rational design of organic thermoelectric materials is to realize simultaneously high electrical conductivity and high induced-voltage in response to a thermal gradient, which is represented by the Seebeck coefficient. Conventional wisdom posits that the polymer alone dictates thermoelectric efficiency. Herein, we show that doping — in particular, clustering of dopants within conjugated polymer films — has a profound and predictable influence on their thermoelectric properties. We correlate Seebeck coefficient and electrical conductivity of iodine-doped poly(3-hexylthiophene) and poly[2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2′′;5′′,2′′′-quaterthiophen-5,5′′′-diyl)] films with Kelvin probe force microscopy to highlight the role of the spatial distribution of dopants in determining overall charge transport. We fit the experimental data to a phonon-assisted hopping model and found that the distribution of dopants alters the distribution of the density of states and the Kang–Snyder transport parameter. These results highlight the importance of controlling dopant distribution within conjugated polymer films for thermoelectric and other electronic applications.

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Section: Resultsmentioning

confidence: 99%

Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films

et al. 2019

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“…The modulation of material properties through microscopic manipulation of GB properties in terms of segregation engineering does not only work for metallic systems [5][6][7], but also for semiconductors, e.g. Si-based materials [8][9][10][11][12]. The alien elemental doping plays an important role in modulating the electrical properties of Si-based nano-devices [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Phosphorous (P) and arsenic (As), as important n-type dopants, are usually ion implanted in Si wafers for nano-scale semiconductor applications [20][21][22][23][24]. One typical example is the metal-oxide semiconductor field effect transistor (MOSFET) [12,19,25]. The uniformity of doping elements is important for the electrical parameters of these Si-based microelectronic devices [25,26].…”

Section: Introductionmentioning

confidence: 99%

“…The uniformity of doping elements is important for the electrical parameters of these Si-based microelectronic devices [25,26]. Nevertheless, GB segregation usually occurs in the process of post-implant annealing, resulting in an non-uniform distribution of dopants [12,27]. This dopant concentration difference at GB and grain interior is especially unwanted since it can induce characteristic electrical variability and drastically change the threshold voltage of MOSFET [11,25,28,29].…”

Section: Introductionmentioning

confidence: 99%

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Revealing the factors influencing grain boundary segregation of P, As in Si: Insights from first-principles

Zhao

2019

Acta Materialia

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“…A plethora of information about the (matrix and dopant) concentration and spatial distribution of atoms, segregation at interfaces and defects, solute clustering, etc. [2]- [5], can be extracted with APT, ultimately enabling a local assessment of various parameters that are critical to device development and which require precise control.…”

Section: Introductionmentioning

confidence: 99%

Potential sources of compositional inaccuracy in the atom probe tomography of InxGa1-xAs

et al. 2020

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With the objective of applying Laser-Assisted Atom Probe Tomography to compositional analysis within nanoscale InGaAs devices, experimental conditions that may provide an accurate composition estimate were sought by extensively studying an InGaAs blanket film.Overall, the determined Arsenic concentration was found to exhibit an electric field dependent deficiency, which was more pronounced at low field conditions, whereas, the determined group III site-fraction remained more or less independent of analysis conditions and in close agreement with the nominal value. In this study, we investigate and discuss the mechanisms that could potentially contribute to As underestimation. Given the field dependence observed, the phenomena occurring between low and high field conditions are compared. At low field, the tendency of As to field evaporate in significant amounts as multiply charged cluster ions (Asn i+ with n as large as 9 and i=1,2,3) is shown to be a significant source of compositional inaccuracy. These clusters may lead to peak overlap in the mass spectrum (e.g. the peak at 150 Da may represent As4 2+ or As2 + or both), thereby creating an uncertainty in the quantification. Emitted clusters may also dissociate with the likelihood of neutral generation and multi-hit losses being non-negligible. Experimental studies and density functional theory calculations are presented to characterize cluster stability and its contribution to measurement uncertainty. Under high field conditions, although fewer clusters are detected and the composition appears more accurate, the emergence of two additional mechanisms, i.e., multi-hits and DC evaporation, may degrade the data quality. The challenges in evaluating the impact of all these loss mechanisms are examined in detail. Finally, we show that for InGaAs under UV illumination, due to the lasertip interaction, the resulting asymmetric electric field distribution across the apex introduces local concentration variations.

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Investigation of dopant clustering and segregation to defects in semiconductors using atom probe tomography

Cited by 11 publications

References 25 publications

Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films

Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films

Revealing the factors influencing grain boundary segregation of P, As in Si: Insights from first-principles

Potential sources of compositional inaccuracy in the atom probe tomography of InxGa1-xAs

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