In this paper we review the FinFET technology, from concept , device design, fabrication to challenges and opportunities. The FinFET is a new concept in Silicon Carbide power devices [1-4]. In Silicon, the FinFETs are used in ULSI applications to increase the gate density (3nm gate) and improve the subthreshold slope. In Silicon Carbide, the FinFET has a very different purpose, that of significantly increasing the effective mobility [1-4]. The increase channel mobility results directly in a lower specific on-state resistance and aa a result higher device efficiency or indirectly could lead to reliability improvement, longer short-circuit endurance or lower Miller capacitance which results in faster and less lossy commutation. Numerous studies have been dedicated to understanding the interface between the oxide and Silicon Carbide and improving the electron mobility at this interface [5-7]. It has been found that there are several mechanisms limiting the mobility, among which the most important is the Culombic scattering, followed by phonon and surface scattering [8]. Several methods involving oxide deposition and annealing (e.g. in Hydrogen [7]) have been investigated in order to minimize the interface charge and traps which are responsible for Coulombic scattering, The motivation of this work is to provide an alternative approach, based on FinFET structure to improve the effective mobility at this interface. Fig. 1 shows schematically a FinFET designed for 1kV breakdown. Different pitches between adjacent trenches (i.e. fins) have been designed and fabricated. The FinFET effect is observable below 250nm. We define the mild FINFET region, around the 150nm line, where the two depletion regions associated with adjacent trenches meet and the charge in the depletion region is restricted to grow. In the strong FinFET effect full bulk inversion is established and the depletion region in the p well is no longer present. This is below 50nm. A SEM photograph of a fabricated FinFET with 144nm fin is shown in Fig.2 [3]. Fig. 3 shows the transfer characteristics [3], highlighting the higher subthreshold slope due to the increased effective mobility and lower threshold voltage of FinFET structures. Fig. 4 shows the difference in band diagrams of a FinFET compared to a classical structure. It is worth noting that the electron charge in the strong FinFET is significantly increased while in the middle of the bulk channel the transversal electric field is zero. The threshold voltage can decrease significantly (towards a normally-on structure) with lower fins, however, interestingly, the variation of the threshold voltage with temperature is milder for the FinFET when compared to a classical FET. This is proven by both experimental results and TCAD simulations which are in excellent agreement. The increased mobility in the FinFET (by more than 2X even in the mild geometry) resulted in a record FOM as shown in Fig. 6. Acknowledgement and References I would like to acknowledge the team at Mirise, Japan, H. Fujioka, H. Tomita, T. Nishiwaki, T. Kumazawa, M. Kumita, M. Okuda, H. Fujiwar and others for the work done on FinFETs and in particular the advanced fabrication of these devices. I would also like to thank Q.Wang for his contribution to FinFET modelling. [1] F. Udrea and H. Kang, UK 805288.6, priority date 29.03.2018, published 02.10.2019 [2] T. Kato et al., 32nd ISPSD, Vienna, 62 (2020). [3] F. Udrea et al., 33rd ISPSD, Nagoya, 75 (2021). [4] F. Udrea et al, 34th ISPSD, Vancouver, 253 (2022) [5] M. Cabello et al., Mater. Sci. Semicond. Process. 78, 22 (2018). [6] T. Kobayashi et al., Appl. Phys. Express 13, 091003 (2020). [7] T. Kimoto. Proc. Jpn. Acad., Ser. B 98 (2022) [8] K. Naydenov et al, . Engineering Research Express. 3 (2021)