Comparison of inter-diffusion coefficients for Ni/Cu thin films determined from classical heating analysis and linear temperature ramping analysis by means of profile reconstruction and a numerical solution of Fick’s law

Joubert, H. D.; Terblans, J.J.; Swart, H.C.

doi:10.1016/j.nimb.2009.05.047

Cited by 4 publications

(6 citation statements)

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“…[1] Diffusion coefficients provide an insight into how much mixing between the elements of a thin film couple takes place after a certain time and at an elevated temperature, [2] similar to the conditions experienced by semiconductor chips during its lifetime. The inherent problem with diffusion parameters available in literature for Ni/Cu thin films is the variation in the structure and composition of the thin film couple.…”

Section: Introductionmentioning

confidence: 99%

“…[3] The difference in microstructures results in diffusion parameters that have a very wide range of values, as indicated in Table 1. Of further concern is the annealing methods used in certain studies of thin film diffusion couples, [2] where the time of annealing is taken as the time between insertion of a sample into the furnace and removal of the sample from the furnace (classical heating), ignoring the mechanisms that govern heat transfer. [2] Classical thin film diffusion studies rely on annealing of many samples for different times and at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Of further concern is the annealing methods used in certain studies of thin film diffusion couples, [2] where the time of annealing is taken as the time between insertion of a sample into the furnace and removal of the sample from the furnace (classical heating), ignoring the mechanisms that govern heat transfer. [2] Classical thin film diffusion studies rely on annealing of many samples for different times and at different temperatures. Interface broadening results from such a heat treatment and analysis of this broadening yields the diffusion coefficient for the system being investigated.…”

Section: Introductionmentioning

confidence: 99%

“…In this study, a linear heating scheme for binary thin film diffusion couples described in Ref. [2] was expanded to bypass the effect that heat transfer mechanisms have on classical heat treatments, by using a programmed heat treatment that involves linearly ramping and cooling a sample under ultra high vacuum (UHV) 130.5 ± 13 [8] 2 × 10 −5 228.7 [9] 6.93 × 10 −7 90.4 [10] 1.4 × 10 −14 106.1 Figure 1. Representation of the change in the diffusion coefficient during a temperature ramp.…”

Section: Introductionmentioning

confidence: 99%

“…The drawback in using temperature ramping for diffusion studies is that the diffusion coefficient is not constant during the heat treatment. One can numerically solve Fick's second law [2] and incorporate linear ramping into the numerical calculation. The constants of diffusion are determined from the calculations.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Determining the diffusion coefficient of Ni in Cu from a Ni/Cu thin film using linear heating, scanning Auger microscopy and a numerical solution of Fick's second law

Joubert

Terblans

Swart

2010

Surface & Interface Analysis

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In previous studies, linear temperature ramping was used to determine diffusion coefficients from bulk-to-surface segregation experiments of a low concentration solute. Thin film diffusion studies usually employ a classical heating regime, where a sample's annealing time is taken as the time between insertion and removal from a furnace. The aforementioned study type assumes that the time it takes to heat up a sample after insertion is instantaneous, while the sample cools down instantaneously after removal from the furnace. This assumption is incorrect, as it does not compensate for the various mechanisms that govern heat transfer. In order to eliminate the uncertainty, a linear ramping regime is used and samples were annealed inside an ultra high vacuum (UHV) environment with a programmed linear heating scheme. After each anneal, a depth profile was obtained by simultaneously bombarding the sample with Ar + ions and monitoring the exposed surface with an electron beam which excites Auger electrons, among others. The depth profiles were normalised and the time scale converted to depth. In order to compare the diffusion profiles obtained from classical annealing studies to the linearly ramped studies, the diffusion coefficient obtained for a classical study of Ni diffusing in Cu was inserted into a numerical solution of Fick's second law, modified to include linear temperature ramping. A diffusion coefficient was also obtained from linearly ramped samples. Comparison of the diffusion profiles calculated with the diffusion coefficients obtained from classical heating and linear heating showed a large discrepancy between the profiles.

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Section: Introductionmentioning

confidence: 99%