Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and Polycrystalline Ru Substrates

Round 1

Reviewer 1 Report

Reviewer Recommendation and Comments for manuscript materials-1505130 with the title: “Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and Polycrystalline Ru Substrates”, authors: Wenbo Shaoa,b, Yunkai Suna and Giovanni Zangaria.

            The authors present the electrodeposition of Cu-Ag film on two different substrate represented by Si and Ru. Phase composition of the Cu-Ag electrodeposits was examined by SEM and XRD methods. The characterization of the electrodeposition processes was completed by the study of the electrodeposition kinetics.

The article may be published after revision.

The main comments that I find useful for improving the quality of the article are presented below:

»line 4. The names of the authors are correct? Shaoa, Suna and Zangaria?

»line 19. The Introduction part requires introducing more data related to Cu, Ag and Cu-Ag electrodeposition.

»line 73. Y axis of Figure 1 is current or current density? Correction must be made throughout the manuscript. See also Figure 3 and Figure 6.

»line 82. Figure must indicate also the alloy composition in Cu, AgO, Ag2O, CuO, Cu2O.

»line 103-105. ”When Ag(I) is added to the Cu deposition bath, an additional peak occurs at -0.2VSMSE, corresponding to the reduction of Ag(I)/Ag.” According to Figure 1, the reduction potential of Ag(I) is -0.034 V. The statements require further clarification.”

»lines 92. Figure 3. Experimental results indicate Cu dissolution at -0.36 V. Standard reduction potentials of Cu indicate dissolution of Cu at -0.36 V?

»line 116. The XRD analysis of the Cu-Ag deposits on Ru substrate must be introduced.

»line 141. ”(estimated by the thicknesses in Fig.1)” Why Figure 1 and not Figure 3? for Si substrate.

»General remarks. In the case of Ru substrate, Cu-Ag deposits at different potentials and the same electrolytic bath are analyzed by SEM. In the case of Si substrate, Cu-Ag deposits at the same potential and different electrolytic baths are analyzed by SEM. The use of similar experimental conditions is recommended. Thus effective discussions and comparisons can be made.

»General remarks. Please move Figures 1 and Figure 2 to section 3.1. Cu-Ag at Ruthenium Substrates. Please move Figures 3 to section 3.2. Cu-Ag at Si(001) Substrates.

»General remarks. Figures 1 and 3 must contain the CV of Ru and Si substrate in H2SO4. (without CuSO4 or AgNO3). In this way the electrode processes of the substrate itself are highlighted.

»The typos must be corrected.

e.g.

CuSO4, H2SO4, AgNO3, H2O2, CO2

line 9 - 0.4V

line 12 - 0.1mM

line 13 - 0.01mM

line 33 - pronounced.[25]

line 36 - phenomena.[26]

line 38 - substrates.[27]

line 44 - 5nm Ta

line 51 - 1cm2

line 55 - 10mM, 0.5M, 0.5mM

line 72 - measurements.[27]

line 79 - databases.[30]

line 89 - 0.1 VSMSE

etc.

»The Materials journal require a specific format of references, authors must pay more attention in their writing. No reference is written according to the format required by the journal.

»There are some grammar and typing mistakes.

»The authors must revise the entire manuscript.

Author Response

Thank you very much for your comments! Replies to your comments have been attached as a word document.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript "Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and
Polycrystalline Ru Substrates" reports on the investigation of the characteristics of the electrodeposition of Cu-Ag films from acidic sulfate bath at n-Si(001) andpolycrystalline Ru substrates and on the corresponding morphological/structural characterizations.

From a general point of view, the topic of the manuscript is interesting and worth of investigation. Generally, the manuscript is clear, well-written, and well-organized. Figures are clear and appealing.

The introduction clearly states the aim of the work and sharply inserts the work within a scientific and technological framework of general interest. Possibly, however, it could be improved to better highlight the originality of the work with respect to previous literature and to make it more appealing for a wider readership.

The experimental section is complete and detailed. The experimental approaches and methods are clearly described, are reliable and strongly founded. Several experimental techniques are crossed towards a complete characterization of the produced systems.

The results are interesting and potentially useful for researchers working in the related fields. The discussions of the results are reliable since based on general physical and chemical concepts allowing to elucidate the basic involved microscopic parameters and processes and allowing some new and interesting insights. Worth of mention is the effort by the authors in the quantitative discussions of the experimental data.

Overall, I find a valuable and interesting manuscript which deserves publication in Coatings after some minor revisions to make the manuscript more appealing for a wider readership and to clarify some aspects.

1) Introduction could be improved to better highlight the originality of the work with respect to previous literature and to make it more appealing for a wider readership.

2) Discussion:

a) A typical Ag-based alloy is AuAg which is used widely in several applications.The AgCu and AuAg alloys have several differences and some similarities. A critical comparison of the peculiarities of the AgCu and AuAg alloys, by strictly referring to the corresponding phases diagrams, would be useful for readers and would make the paper more appealing for a wider readership. See, as examples: Superlattices and Microstructures 103, 28 (2017); ACS Nano 10, 188 (2016).

b) "Hindrances during Cu dissolution may also be caused by the positive Schottky barrier between deposited Cu and the n-Si(001": please, specify what do you mean with "positive". In addition, please report the value of possible range of values.

c) "Thus, we consider that this decrease of the Cu dissolution peak would be originated by Cu deposits detachment from the Si substrate, related to the poor wettability of Cu grains at Si(001) substrate": please, refer to more quantitative evaluations by reporting, for example, values for the adhesion energy or values for Si and Cu surface energies and inetrface energies. Generally, for example, metals as Au (and possibly also Cu) show a low adhesion on SiO2, however a better adhesion on Si (J. Appl. Phys. 107, 104321 (2010)).

Author Response

Thank you very much for your comments! Replies to your comments have been attached as a word document.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Reviewer Recommendation and Comments for manuscript coatins-1511309 with the title: “Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and Polycrystalline Ru Substrates”, authors: W. Shao, Y. Sun and G. Zangari.

            The authors took into account the comments of the referents and introduced new comments / paragraphs in the revised form of the article.

However, it seems that the revision was done in a hurry and there are still some minor corrections to be made.

The journal template is not used correctly. Keywords and copyright were deleted!

The final section has been deleted. Thus, the authors' contribution, funding, etc. are missing.

The typos must be corrected.

e.g.

replace 0.1mM with 0.1 mM

replace -0.3V with -0.3 V

etc.

Author Response

Thank you very much for your comments. We have addressed the questions in the attached document.

Author Response File: Author Response.docx