Minor elements determination and evaluation of diffusion/segregation effects on ultra-thin layers using pulsed-RF-GD-TOFMS
Subject:
Glow Discharge
Secondary Ion Mass Spectrometry
Surface
Tlc/Ms
Time-Of-Flight Spectrometer
Publication date:
2011Publisher version:
http://dx.doi.org/10.1039/c1ja10075kCitación:
Journal of Analytical Atomic Spectrometry, 26(8), p. 1604-1609 (2011); doi:10.1039/c1ja10075kDescripción física:
p. 1604-1609Abstract:
Depth profile analyses of ultra-thin layers and their interfaces are investigated, using an innovative Pulsed-radiofrequency Glow Discharge Time-of-Flight Mass Spectrometer (pulsed-rf-GD-TOFMS), to obtain information about the presence of minor elements and to evaluate segregation/diffusion processes at the interfaces. A series of ultra-thin Nb/Al1−xCox bilayers, deposited on Si wafers by dc-magnetron sputtering, is analyzed. An Al1−xCox layer is first deposited on the Si substrate with controlled constant thickness (tAlCo = 6 nm), and different stoichiometries (Co atomic concentration, x = 0, 0.015, 0.035, 0.045, 0.09, 0.35). Then, a Nb layer is deposited on top of the AlCo one, with a thickness tNb = 50 nm that is also kept constant along the whole series. Qualitative depth profiles of those layered sandwich-type samples are determined using our pulsed-rf-GD-TOFMS setup, indicating segregation of Al and Co and diffusion of Co into the Si substrate, as a function of the Co atomic concentration in the AlCo internal layer. Additionally, a linear calibration curve was achieved plotting the Co atomic concentration versus the total integrated Co ion signal, allowing the Co quantification in ultra-thin layers ([similar]6 nm). Moreover, Secondary Ion Mass Spectrometry (SIMS) was used as a reference technique to validate the high analytical potential of pulsed-rf-GD-TOFMS for the analysis of ultra-thin layers and interfaces. The comparative analytical performance of both techniques is discussed.
Depth profile analyses of ultra-thin layers and their interfaces are investigated, using an innovative Pulsed-radiofrequency Glow Discharge Time-of-Flight Mass Spectrometer (pulsed-rf-GD-TOFMS), to obtain information about the presence of minor elements and to evaluate segregation/diffusion processes at the interfaces. A series of ultra-thin Nb/Al1−xCox bilayers, deposited on Si wafers by dc-magnetron sputtering, is analyzed. An Al1−xCox layer is first deposited on the Si substrate with controlled constant thickness (tAlCo = 6 nm), and different stoichiometries (Co atomic concentration, x = 0, 0.015, 0.035, 0.045, 0.09, 0.35). Then, a Nb layer is deposited on top of the AlCo one, with a thickness tNb = 50 nm that is also kept constant along the whole series. Qualitative depth profiles of those layered sandwich-type samples are determined using our pulsed-rf-GD-TOFMS setup, indicating segregation of Al and Co and diffusion of Co into the Si substrate, as a function of the Co atomic concentration in the AlCo internal layer. Additionally, a linear calibration curve was achieved plotting the Co atomic concentration versus the total integrated Co ion signal, allowing the Co quantification in ultra-thin layers ([similar]6 nm). Moreover, Secondary Ion Mass Spectrometry (SIMS) was used as a reference technique to validate the high analytical potential of pulsed-rf-GD-TOFMS for the analysis of ultra-thin layers and interfaces. The comparative analytical performance of both techniques is discussed.
ISSN:
0267-9477Identificador local:
20111369
DOI:
10.1039/c1ja10075kPatrocinado por
This work is supported by the projects (MAT2010-20921-C02, FIS2008-06249 and HP2008-0032) of the Ministry of Science and Innovation of Spain.
Id. Proyecto
MAT2010-20921-C02
FIS2008-06249
HP2008-0032
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