Reflectometry studies of the oxidation kinetics of thin copper films

Njeh, Anouar; Wieder, Thomas; Fueß, H.

doi:10.1002/sia.1421

Cited by 31 publications

(10 citation statements)

References 7 publications

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“…growth of thickness of the oxide as a function of time, and they are summarised in Fig 11. A number of theories have been proposed [277][278][279][280] , mostly based on the Cabrera and Mott 281 theory and they postulate that, under the assumption of uniform epitaxial growth, the thickness of a metal oxide increases following an inverse logarithmic rate law for very thin films (up to 7.3 nm for Cu) and a cubic law for thicker films (up to 1.5 µm). A number of works 228,274,282,283 find qualitative agreement with the Cabrera-Mott theory, however linear oxide growth has been observed in other studies 263,284,285 , as well as power (n < 1) 286 or parabolic law 287 .…”

Section: Long-term Copper Oxidationmentioning

confidence: 70%

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Gattinoni

Michaelides

2015

Surface Science Reports

270

258

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The oxidation and corrosion of metals are fundamental problems in materials science and technology that have been studied using a large variety of experimental and computational techniques. Here we review some of the recent studies that have led to significant advances in our atomic-level understanding of copper oxide, one of the most studied and better understood metal oxides. We show that a good atomistic understanding of the physical characteristics of cuprous (Cu 2 O) and cupric (CuO) oxide and of some key processes of their formation has been obtained. Indeed, the growth of the oxide has been proven to be epitaxial with the surface and to proceed, in most cases, through the formation of oxide nano-islands which, with continuous oxygen exposure, grow and eventually coalesce. We also show how electronic structure calculations have become increasingly useful in helping to characterise the structures and energetics of various Cu oxide surfaces. However a number of challenges remain. For example, it is not clear under which conditions the oxidation of copper in air at room temperature (known as native oxidation) leads to the formation of a cuprous oxide film only, or also of a cupric overlayer. Moreover, the atomistic details of the nucleation of the oxide islands are still unknown. We close our review with a perspective on future work and discuss how recent advances in experimental techniques, bringing greater temporal and spatial resolution, along with improvements in the accuracy, realism and timescales achievable with computational approaches make it possible for these questions to be answered in the near future.

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Section: Long-term Copper Oxidationmentioning

confidence: 70%

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Gattinoni

Michaelides

2015

Surface Science Reports

270

258

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“…[10][11][12][13] Njeh et al 10 discuss the oxidation of copper thin films in air using x-ray reflectometry and x-ray diffraction at temperatures below 250 C. Ellipsometry, using 350 nm to 850 nm light, has also been employed successfully to characterize the oxidation kinetics by Iijima et al 11 It was shown by Zhong et al 12 that the measurement of the sheet resistance of copper layers during oxidation can also give information about the oxidation kinetics. In the latter technique, the change in sheet resistance was correlated with the thinning of the copper metal layer due to oxidation.…”

Section: Introductionmentioning

confidence: 99%

Oxidation kinetics of nanoscale copper films studied by terahertz transmission spectroscopy

Ramanandan

Ramakrishnan

Planken

2012

Journal of Applied Physics

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Terahertz (THz) transmission spectroscopy is used to measure the oxidation kinetics of copper thin films evaporated on silicon substrates. The transmission of broadband THz pulses from 1 to 7 THz through the copper film is measured while it gets oxidized at an elevated temperature in ambient air. The change in the transmitted THz electric field is correlated with the growth of the cuprous oxide layer and the decrease in thickness of the copper layer. Oxidation curves were obtained for heating temperatures of 120-150 C and were found to follow a parabolic rate law. Using the Arrhenius equation, we calculate an activation energy for diffusion of 0.55 eV. By measuring the THz transmission through unoxidized copper layers of several thicknesses, we also measured the optical properties of thin copper films around the percolation threshold thickness of 7 nm. Around the percolation transition, the optical properties of freshly deposited copper thin films are very different from that of copper layers of the same thickness remaining after partial oxidation of thick copper films. V C 2012 American Institute of Physics. [http://dx

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“…The formation of Cu 2 O was probably owing to the oxidation of a few layers of sintered copper during the heating process. 24) The results of the EDS analysis also suggested that a few sintered layers were in the form of a solid solution of the silver and copper nanoparticles (point 1 in Table 1), indicating that some of the copper nanoparticles were alloyed with the silver during the formation and sintering of the copper nanoparticles.…”

Section: Tensile Strength Of the Jointsmentioning

confidence: 97%

Bondability of Copper Joints Formed Using a Mixed Paste of Ag<sub>2</sub>O and CuO for Low-Temperature Sinter Bonding

et al. 2013

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The bondability of copper joints formed using a mixed paste of silver oxide (Ag 2 O) and copper oxide (CuO) that contained reducing solvents was evaluated in order to achieve bonds that exhibited high migration tolerance and could serve as Pb-free alternatives to the conventional bonds formed using high-melting point solders in electronics packaging. The Ag 2 O particles reduced into silver nanoparticles at 150°C, whereas the CuO reduced into copper nanoparticles about 300°C. The joints formed using the Ag 2 O/CuO mixed paste, when heated to the appropriate levels, exhibited bondability superior to that of conventional Pb5Sn joints. The oxide film formed on the copper substrate was reduced by the combustion of polyethylene glycol 400, and bonding was achieved between the sintered layer and the copper substrate. A longer period resulted in the oxidisation of a few layers of sintered copper layers into Cu 2 O. The ion-migration tolerance of the Ag 2 O/CuO mixed paste was approximately four times that of a layer of pure sintered silver.

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Reflectometry studies of the oxidation kinetics of thin copper films

Abstract: Oxide formation on magnetron-sputtered thin copper films (35 nm thickness) was studied by x-ray reflectometry and grazing incidence x-ray diffraction. The films were oxidized in air at temperatures of 175•

Cited by 31 publications

References 7 publications

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Atomistic details of oxide surfaces and surface oxidation: the example of copper and its oxides

Oxidation kinetics of nanoscale copper films studied by terahertz transmission spectroscopy

Bondability of Copper Joints Formed Using a Mixed Paste of Ag<sub>2</sub>O and CuO for Low-Temperature Sinter Bonding

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