Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors describe the fabrication of multilayered Ag based reflectors for MEMS applications. The topic of the paper is interesting and the results obtained are significant. My main concern is about how the paper is written and how the outcomes of the experimentation are presented. From this point of view, I can make the following observations:

1) Figure 1: the “CWL” acronym is not defined.

2) Lines 74 and 75: what is the meaning of these acronyms?

3) Table 1: how is the standard deviation of the data calculated? Is it calculated from multiple measures carried out on different zones of the same sample or from different samples? In the first case, can the authors comment on the uniformity of the coatings on the whole device?

4) Figure 2: probably the “silver” and “glass” labels have been switched in the insert on the right. If I understand correctly, the glass should be outside the circular pattern.

5) Regarding the wet etch process, I do not clearly understand the origin of the remaining photoresist. Was the stripping process optimized?

6) Some figures have not been referenced in the text (figure 4, figure 5, figure 6, …)

7) Line 132: I do not understand what “ruptured” means. Maybe over etched?

8) Line 215: do the authors mean here “between the lowest and the highest point”? If not, what is the meaning of this sentence?

9) Line 217: how what the 0.6 µm value measured?

10) Line 219: “tape demolition test”? Please use “tape peel test”.

11) Lines 315 and 318: the term “artifacts” is totally misleading. These are defects. What is their nature and origin?

12) Figure 15: how was this data simulated? Why there is noise below 450 nm?

Comments on the Quality of English Language

In addition to these observations, it is in general necessary to improve the English of the manuscript. Some of the most critical examples, not exhaustive, are: line 116, lines 146-147, line 182, line 188, lines 198-199, line 250, line 275, line 355. Please revise thoroughly the manuscript.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is a quite interesting research paper that probably can be recommended for publication, but only after clarifying and detailing some parts of the text.

1.     The introduction does not reveal the idea of using exactly AlN.

2.     More recent results should be discussed in the introduction, this will allow a clearer assessment of the relevance and novelty of this work.

3.     Figures 9, 10, 14. The caption to the figures is incorrect; the spectral range shown in the figures corresponds more than half to the visible range. Note that FTIP data correspond to different spectral range. See for example: Fig. 8 in  the following paper: C Balasubramanian et al 2006 J. Phys.: Condens. Matter 18 S2095DOI 10.1088/0953-8984/18/33/S25

In general, the manuscript is interesting and can be recommended for publication after constructive reflection on the above comments.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Behl presented the fabrication and characterization of a AlN/Ag/AlN-reflector stack for Fabry-Pérot-Interferometer (FPI) applications. I suggest major revisions for the manuscript. 

1. The authors may need to polish the logical flow and English language to make it more concise and focused. In presenting the results, the authors always mixed too many characterization technique details with the experimental data, and I can easily get lost and cannot quite grasp the significance of the results. 

2. In the introduction, the author may need to add more dicussions on previous research studies on metallic thin films for FPI. It will be nice to include research background on what have been achieved, what the current challenges are, and how the manuscript will address the challenges etc. 

3. The authors used wet etch, dry etch, and lift off for fabrication fo Ag thin films. But according to the current manuscript, they are all not fully optimized. Is it possible to do further optimizations and present more mature data?

4. In the last section, the authors only used a simulation to prove that the fabricated mirrors are suitable for FPI applications. It may be more resonable to have some experimental demonstrations. 

Comments on the Quality of English Language

An extensive editing of the language is required for the current manuscript. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript presents the characterization results of thin AlN/Ag/AlN reflector stacks. The following comments should be considered in the revision:

1. The characterization part mainly presents the results one by one in details, without a clear summary or comparison. It's better to have a table to compare the properties of AlN/Ag/AlN with Ag, or other state-of-the-art works.

2. Section 2.2 presents an unsuccessful dry etch. The authors should follow correct dry etch process and present results, otherwise this part doesn't provide readers useful information.

Comments on the Quality of English Language

Minor editing

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors addressed al my points. The manuscript can be published.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have addressed my comments and I recommend to accept the current manuscript for publication. 

Comments on the Quality of English Language

The quality of English of the revised version is overall good.