SiC/Si Hybrid Substrate Synthesized by the Method of Coordinated Substitution of Atoms: A New Type of Substrate for LEDs
, Lev K. Markov 2, Alexey S. Pavlyuchenko 2, Irina P. Smirnova 2, Andrey V. Osipov 1,*, Alexander S. Grashchenko 1, Andrey E. Nikolaev 2, Alexey V. Sakharov 2, Andrey F. Tsatsulnikov 3 and Genadii V. Sviatets 4Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper by Sergey A. Kukushkin et al. proposes proposes a new type of substrate for manufacturing LEDs based on AlInGaN heterostructures. Instead of depositing SiC layers on the surface of Si using the conventional method, a new method involving coordinated substitution of atoms (MCSA) to form the SiC layer is proposed. The paper details the technology of manufacturing LEDs on SiC/Si substrates obtained by the MCSA and elaborates on the benefits of using these substrates in LED production. However, in my opinion, the manuscript is suitable for publication after some concerns that the authors should considered before its publication.
1. The introduction part should be enriched with recent references.
2. In this paper should be added some definitions of membrane preparation methods, such as the standard growth method.
3. In the paper, line 400, wafer processing of light emitting diode heterostructures should be given highlighting several advantages of applying SiC/Si substrates compared to sapphire substrates.
Comments on the Quality of English LanguageThat's fine.
Author Response
Dear Colleques,
The authors would like to thank the Reviewers for the interest to this work and important comments. We have thoroughly checked the manuscript and made required corrections in the text where possible. The Reviewers’ comments and our answers are presented below. Changed text is highlighted in yellow.
Reviewer #1
- The introduction part should be enriched with recent references.
A new reference to a modern review of microLED [1] has been added to line 41. The following text is added to line 234-242: “Note that the structure and properties of SiC films grown on Si by MCSA and VMCSA methods have been studied in detail previously. The composition, structure, thickness and properties of the films were characterized by XRD, RHEED, Raman spectroscopy, and spectroscopic ellipsometry. Data obtained by the TEM method were also taken and analyzed. In addition, X-ray photoelectron spectroscopy (XPS), Auger electron spec-troscopy, Rutherford backscattering (RBS), X-ray reflectometry, and IR spectroscopy were used. The SiC layers were also studied by photoelectron spectroscopy using syn-chrotron radiation in the energy range of 80-450 eV. These studies were summarized in reviews [12,18,19,22]”.
- In this paper should be added some definitions of membrane preparation methods, such as the standard growth method.
This issue is discussed at length on pages 5-6, lines 201-242. We call standard growth methods all growth methods in which all precursors from which the films grow are supplied to the substrate surface from an external environment. The following text has therefore been added to lines 234-242.
“Note that the structure and properties of SiC films grown on Si by MCSA and VMCSA methods have been studied in detail previously. The composition, structure, thickness and properties of the films were characterized by XRD, RHEED, Raman spectroscopy, and spectroscopic ellipsometry. Data obtained by the TEM method were also taken and analyzed. In addition, X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, Rutherford backscattering (RBS), X-ray reflectometry, and IR spectroscopy were used. The SiC layers were also studied by photoelectron spectroscopy using syn-chrotron radiation in the energy range of 80-450 eV. These studies were summarized in reviews [12,18,19,22].”
- 3. In the paper, line 400, wafer processing of light emitting diode heterostructures should be given highlighting several advantages of applying SiC/Si substrates compared to sapphire substrates.
The article is supplemented with the following text:
- lines 431-438: “Since the conventional value of the thermal conductivity of silicon at is and the thermal conductivity of leucosapphire at the same temperature is with the same substrate thickness, LEDs on silicon substrate will be more than 6 times more efficient when removing heat from the active area of the chip; which, in its turn, leads to minimization of overheating of the active area of the chip. Accordingly, the operation of the chip at lower temperatures means a higher quantum efficiency as well as less degradation of chip parameters during operation.”
- lines 445-453: “As one knows the hardness of silicon and sapphire is 7 and 9 on the Mohs scale, respectively. Hence, the procedure for thinning the silicon substrate, which is used to reduce thermal resistance between the p-n junction and the heat sink, will proceed at high speeds; in the case of silicon, it becomes possible to use a wider range of abrasives (including less expensive ones) than for sapphire. In the case of sapphire, as a rule, expensive laser cutting machines are used for cutting wafers into individual chips, while cutting silicon wafers can be easily carried out using cheaper methods such as scribing or cutting with diamond disks.”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript proposes a novel approach for the LED substrate (SiC/Si) by involving the coordinated substitution of atoms (MCSA) method for SiC formation. All the details of fabrication are explained explicitly. Overall, the manuscript is immaculate and well-written. However, it still needs some major changes before it is ready to be published.
1. In page 9, the author mentioned that “incorporating a SiC layer with minimal thickness would not cause overheating of the active section of the chip face-up design.” This may be due to the higher thermal conductivity of SiC than Si. But such reasoning is not convincing, please provide further explanation by supporting previous reference.
2. Overall, the image resolution is insufficient. Please improve the quality of Figure 8 and Figure 12 and increase the font size in the figure. Then, both sides of Figure 10 (a) (b) and Figure 13 (a) (b) should be in the same symmetrical size.
Author Response
Dear Colleques,
The authors would like to thank the Reviewers for the interest to this work and important comments. We have thoroughly checked the manuscript and made required corrections in the text where possible. The Reviewers’ comments and our answers are presented below. Changed text is highlighted in yellow.
Reviewer #2
The manuscript proposes a novel approach for the LED substrate (SiC/Si) by involving the coordinated substitution of atoms (MCSA) method for SiC formation. All the details of fabrication are explained explicitly. Overall, the manuscript is immaculate and well-written. However, it still needs some major changes before it is ready to be published.
- In page 9, the author mentioned that “incorporating a SiC layer with minimal thickness would not cause overheating of the active section of the chip face-up design.” This may be due to the higher thermal conductivity of SiC than Si. But such reasoning is not convincing, please provide further explanation by supporting previous reference.
The following text has been added to lines 423-438:
In [34] the thermal resistance of Si wafers with both thin and thick SiC layers were investigated. As a result, it was found that the thermal conductivity of wafers containing thin SiC layers up to thick corresponds to the thermal conductivity of silicon wafers. Consequently, the inclusion of a minimum-thickness SiC layer does not lead to overheating of the active part of the chip face-up design. In addition, the overall thermal resistance of the p-n junction heat sink circuit for the chip located on hybrid wafers is significantly lower than that of sapphire wafers. Since the conventional value of thermal conductivity of silicon at is , and the thermal conductivity of leucosapphire at the same temperature is for the same substrate thickness, LEDs on silicon substrate will be more than 6 times more efficient in heat removal from the active area of the chip, which, in turn, leads to minimized overheating of the active area of the chip. Accordingly, chip operation at lower temperatures means higher quantum efficiency, as well as less degradation of chip parameters during operation. In the same study [34] it was found that the thermal resistance of thick SiC layers separated from the Si substrate corresponds to the thermal resistance of pure silicon carbide layer of 3C-SiC polytype, i.e., the thermal conductivity of the layer is .
- Overall, the image resolution is insufficient. Please improve the quality of Figure 9 and Figure 12 and increase the font size in the figure. Then, both sides of Figure 10 (a) (b) and Figure 13 (a) (b) should be in the same symmetrical size.
All mentioned Figures were corrected and improved.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors studied " SiC/Si Hybrid Substrate Synthesized by the Method of Coordinated Substitution of Atoms: A New Type of Substrate for LEDs" The as-prepared material was characterized in detail. Still, the work should provide some relevant data to improve the quality of a manuscript before acceptance.
1. It is suggested that the author use a table to compare the results of the material in this paper with the previous works.
2. Photocurrent vs time, and EIS results are suggested to provide.
3. It is recommended that the characterization of optimized materials should be provided (TEM, XRD, XPS..).
4. In the introduction section, the logic of thinking in introducing the background and purpose of the study is not clear enough, please give more knowledge or the significance of the study. The following references are suggested to cite
[1] Hampshire, S., & Kennedy, T. (2022). Silicon nitride–silicon carbide micro/nanocomposites: A review. International Journal of Applied Ceramic Technology, 19(2), 1107-1125.
[2] Ta, Q. T. H., Tran, N. M., & Noh, J. S. (2021). Pressureless manufacturing of Cr2AlC compound and the temperature effect. Materials and Manufacturing Processes, 36(2), 200-208.
Author Response
Dear Colleques,
The authors would like to thank the Reviewers for the interest to this work and important comments. We have thoroughly checked the manuscript and made required corrections in the text where possible. The Reviewers’ comments and our answers are presented below. Changed text is highlighted in yellow.
Reviewer #2
- It is suggested that the author use a table to compare the results of the material in this paper with the previous works.
We have made a table showing some of the properties of SiC/Si hybrid substrates grown by the MCSA and VMCSA methods for LEDs and their comparison with the properties of sapphire substrates and placed it at the end of the conclusion.
- Photocurrent vs time, and EIS results are suggested to provide.
In this work, we describe the main approaches that can be used in the development of light emitting diodes on SiC/Si substrates, as well as the main advantages arising from the use of these substrates. Since the relationship of photocurrent versus time is most relevant for photodetectors not for LEDs, we did not study these dependences.
The electrochemical impedance spectroscopy method (EIS method) has recently been widely used as an informative working tool in various fields of electrochemistry, physics, and materials science. The frequency range of an external alternating electric field applied to a sample typically ranges from 10-6 to 1012 Hz. In this range it is possible to study the dielectric bulk properties of samples and electrode processes, namely, - study of the interface of metal, metal-oxide or semiconductor electrode - electrolyte; - study of dielectric and transport properties of materials; - determination of the mechanism of electrochemical reactions (from studying corrosion processes to reactions in biological and living objects); - study of adsorption processes on electrode surfaces; - study of porous electrode properties. Our work is devoted to the development of technology for obtaining LED heterostructures on silicon carbide and the creation of the LED device itself. EIS method is not needed for these purposes. The purpose of our work is to show the possibilities of a new type of substrate to create LEDs on them. The work shows that this task has been successfully solved and shows that mock-ups of LEDs have been created. The paper also says that the structure of both the substrate itself and the LED heterostructure have been investigated by the most modern methods previously. References to works in which these studies have been described are given in the paper.
- It is recommended that the characterization of optimized materials should be provided (TEM, XRD, XPS.).
The following text has been added to lines 234-242.
« Note that the structure and properties of SiC films grown on Si by MCSA and VMCSA methods have been studied in detail previously. The composition, structure, thickness and properties of the films were characterized by XRD, RHEED, Raman spectroscopy, and spectroscopic ellipsometry. Data obtained by the TEM method were also taken and analyzed. In addition, X-ray photoelectron spectroscopy (XPS), Auger spectroscopy, Rutherford backscattering (RBS), X-ray reflectometry, and IR spectroscopy were used. The SiC layers were also studied by photoelectron spectroscopy using synchrotron radiation in the energy range of 80-450 eV. These studies were summarized reviews [12,18,19,22].»
The following text has been added to lines 331-333.
“The details of the growing technology and data on the structural properties of the structures are given in [32]. In [32], detailed TEM images of the end chipping of all heterostructure layers are given, and a detailed analysis of them is performed.
- In the introduction section, the logic of thinking in introducing the background and purpose of the study is not clear enough, please give more knowledge or the significance of the study. The following references are suggested to cite.
We have taken this reviewer's comment into account and included the following articles in the list of references:
- Hampshire, S.; Kennedy, T. Silicon nitride–silicon carbide micro/nanocomposites: A review. International Journal of Applied Ceramic Technology 2022, 19, 1107-1125, doi:10.1111/ijac.13903.
- Ta, Q.T.H.; Tran, N.M.; Noh, J.-S. Pressureless manufacturing of Cr2AlC compound and the temperature effect. Materials and Manufacturing Processes 2021, 36, 200-208, doi:10.1080/10426914.2020.1819547.
The following text has been added to lines 100-106.
Note that the formation of nanoscale SiC is also possible in the process of synthesis of silicon nitride-silicon carbide micronanocomposites. This synthesis is carried out by sintering grains Si3N4 in the presence of various kinds of polycarbosilanes which are precursors of silicon carbide. These processes are described in detail in the review [13]. However, the synthesis of silicon carbide using sintering methods [13,14] is not suitable for the production of high-performance single-crystal SiC layers on Si, suitable for applications in microelectronics and optoelectronics.
Moreover, we have changed the order of authors (with the consent of all authors), improved the text, corrected typos and improved some Figures.
Sincerely yours,
on behalf of all authors
Andrey Osipov
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsAccept in present form
Author Response
The authors express their deep appreciation to the reviewer for reading the manuscript and for his valuable comments.
Author Response File: Author Response.pdf
