**4. Conclusions**

In the CHALLENGE project, two main different approaches were used to grow 3C-SiC. From one hand, several compliance substrates (pillars, SiGe buffer layer, ISP, etc.) were used to reduce both defects and stress. On the other hand, new bulk growth techniques (PVT or CVD) have been developed to improve the quality of this material. During this work, a new understanding of the defects in this material (protrusions, APBs, SFs, and point defects), their interactions, and the effect of the growth process on their formation and reduction have been obtained. This new understanding has been also helped by the simulation codes developed inside the project (KMCsL, MD, phase field, etc.) and by new characterization techniques (C-AFM).

From this large study on the growth of 3C-SiC, several conclusions can be reported:

• The use of the SiGe buffer layer is interesting and in some cases, some good quality samples can be obtained. The main limitation is that a low-temperature growth should be used and the Ge segregation at the 3C-SiC/Si interface can produce the formation of polycrystalline regions. The process window is narrow and thus this process can be difficult to use in a production line.


Further work should be done to obtain a good material for power devices, but the work performed during this project is a fundamental step for developing new materials for power devices.

**Author Contributions:** Conceptualization, F.L.V., L.M., A.L.M., R.Y., and P.W.; software, G.F., I.D., A.L.M., E.S., A.M., A.S., and L.M.; validation, M.Z. (Massimo Zimbone), C.B., C.C., F.G., M.Z. (Marcin Zielinski)., R.A., M.M., D.C., V.J., P.S., M.S. (Michael Schöler), V.S., and M.K.; writing original draft preparation, F.L.V., M.Z. (Massimo Zimbone), A.L.M., R.A., L.M., V.J., V.S., M.S. (Mikael Syväjärvi) and P.W.; writing—review and editing, F.L.V.; supervision, F.L.V.; funding acquisition, F.L.V. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research study was funded by the European Union within the frame of the project CHALLENGE, grant number 720827.

**Data Availability Statement:** The data can be made available, upon reasonable request, asking to the corresponding author.

**Acknowledgments:** P. Fiorenza, G. Greco, and F. Roccaforte (CNR-IMM) are acknowledged for their contribution in the processing and electrical characterization of devices employed to assess 3C-SiC material quality, and S. Di Franco (CNR-IMM) is acknowledged for the skilled technical assistance.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
