The electrical characterization of nickel silicide Schottky contacts on silicon carbide (4H–SiC) is reported in this article. In spite of the nearly ideal behavior of the contact at room temperature $\text{(n=1.05),}$ the electrical behavior monitored in a wide temperature range exhibited a deviation from the ideality at lower temperatures, thus suggesting that an inhomogeneous barrier has actually formed. A description of the experimental results by the Tung’s model, i.e., considering an effective area of the inhomogeneous contact, provided a procedure for a correct determination of the Richardson’s constant $A^{\mathrm{**}}.$ An effective area lower than the geometric area of the diode is responsible for the commonly observed discrepancy in the experimental values of $A^{\mathrm{**}}$ from its theoretical value in silicon carbide. The same method was applied to Ti/4H–SiC contacts.

In the last ten years, large improvements in the epitaxial silicon carbide processes have been made. The introduction of chloride precursors, the epitaxial growth on large area substrate with low defect density, the improvement of the surface morphology, the understanding of the chemical vapour deposition (CVD) reactions, and epitaxial mechanisms by advanced simulations are just the main results obtained in the homo-epitaxy process of 4H-SiC. After this large stride in the process of SiC epitaxial growth, it is time to collect this knowledge in a review that can be a reference point for the future work in this interesting field. The structure of the review is the following. After an introduction on the evolution and history of the epitaxial growth of 4H-SiC, the main physics parameter of this epitaxial growth process is explained in detail using the traditional Burton-Cabrera-Franck theory and the experimental observations of the surface instability due to the off-axis growths. Then the introduction of chlorinated precursors in the epitaxial process is reviewed and the effect of this new process on Schottky diodes characteristics is shown. The improvement of the epitaxy process is strictly related to the improvement of the simulation of the growth that helps the researchers to understand the effect of different parameters on such complex system. Then, a large part of the review is devoted to the simulations of the CVD systems, the reaction in the gas phase of the different precursors and the surface reaction models. Also, some important results obtained by Monte Carlo simulation on the study of different growth parameters that influence the formation of defects and their evolution are reported. Finally, the influence of different process parameters and in particular of the growth rate on the formation or the reduction of the principal defects that are observed in the epitaxial layer is reviewed. We have divided these defects in four categories: 3D defects (epi-stacking faults and inclusions), 2D defects (stacking faults), 1D defects (dislocations), and 0D defects (point defects). Also the influences of the growth parameters on the surface morphology (step-bunching) and the correlation with defects have been reviewed. In the conclusions the main results on the chloride epitaxy has been summarized and an outlook of this process in the next years has been presented with the actual understanding of the mechanism of the silicon carbide epitaxial growth.

In recent years, several new applications of SiC (both 4H and 3C polytypes) have been proposed in different papers. In this review, several of these emerging applications have been reported to show the development status, the main problems to be solved and the outlooks for these new devices. The use of SiC for high temperature applications in space, high temperature CMOS, high radiation hard detectors, new optical devices, high frequency MEMS, new devices with integrated 2D materials and biosensors have been extensively reviewed in this paper. The development of these new applications, at least for the 4H-SiC ones, has been favored by the strong improvement in SiC technology and in the material quality and price, due to the increasing market for power devices. However, at the same time, these new applications need the development of new processes and the improvement of material properties (high temperature packages, channel mobility and threshold voltage instability improvement, thick epitaxial layers, low defects, long carrier lifetime, low epitaxial doping). Instead, in the case of 3C-SiC applications, several new projects have developed material processes to obtain more performing MEMS, photonics and biomedical devices. Despite the good performance of these devices and the potential market, the further development of the material and of the specific processes and the lack of several SiC foundries for these applications are limiting further development in these fields.