Design for Ultrahigh-Density Vertical Phase Change Memory: Proposal and Numerical Investigation
Round 1
Reviewer 1 Report
In the work,"Design for Ultrahigh-Density Vertical Phase Change Memory: Proposal and Numerical Investigation", authors investigated PCMs using diploid and fourfold memory units technique instead of conventional scheme. Though work done is novel but is not presented well. I have following suggestions (Minor revision) for the authors:
1) It is unclear why range of WGST and Wcs is kept from 12 to 24nm and why TMAX does not show any variation.
2) Elaborate why temperature variation is observed in middle cell only (Fig. 10).
3) Conclude with previous technologies (using a table)
Author Response
Dear reviewer,
Thank you for spending time and efforts on this review process. Please see the attachment to find our reponses to all questions.
Best wishes
D. W. Wang
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Reviewer report:
The manuscript “Design for Ultrahigh-Density Vertical Phase Change Memory: Proposal and Numerical Investigation” is an interesting work in the field of phase switching memories. The main question addressed is the design of high-density integrated schemes such as diploid and fourfold memory units. The topic is original as it adds reduction of sizes of memory cell elements and increasing of integration density. The Paper is well written, the text is clear and easy to read. Conclusions are consistent with the presented data and address the main question.
However, I have some comments which should be addressed before publishing the manuscript.
1 Authors aim to reduce the size of memory cell elements which is necessary both for reducing heat generation and increasing integration density. In this process, the dimensions of elements are reduced to a few nanometers (Table 1). For such dimensions, quantum size effects become considerable and modify material properties such as electrical and thermal conductivities, heat capacity, and Seebeck coefficient. Are these changes taken into account during numerical experiments? Quantum size effects will considerably affect the results presented in Figures: 11, 12, 14, 15, 16, and 17 in which element width is reduced from 20 to 10 nm. Quantum size effects may be negligible in the case of 20 nm width and become considerable for 10 nm.
2 Authors dial with periodic nanostructures with a period of the order of 100 nm. At this size, geometry-induced quantum effects [A. Tavkhelidze et. al Nanomaterials 11, 505 (2021)] are considerable. Note that geometry-induced quantum effects have a much longer scale with respect to quantum size effects and apply to periodic nanostructures only. Once devices introduced by authors are based on periodic nanostructures, geometry-induced quantum effects should be considered.
3 Lines 187-189. It is not clear what is the thickness of the core bar. Is it 24 nm?
Author Response
Dear Reviewer,
Thank you for spending time and efforts on this review process. Please see the attachment to find our reponses to all questions.
Best wishes
D. W. Wang
Author Response File: Author Response.pdf
