Optical Control of the Parameters of Substrates in Silicon-Carbide Epitaxial Structures

Silicon carbide SiC is the basic material of modern extreme and power electronics. The characterization of substrates and SiC-based epitaxial multilayers requires advanced on-line control methods to be developed. In this study, contactless nondestructive optical methods for controlling the kinetic parameters of carriers, layer thickness, and surface quality are demonstrated. Techniques based on the physical processes of the interaction between a photon flux and a SiC single crystal are used. The carrier density and mobility and layer thicknesses in epitaxial multilayers are determined and the substrate surface-treatment quality is characterized by approximating infrared reflectance spectra. The data obtained are verified by independent methods. The proposed algorithm for combined use of these methods ensures the efficient control of substrates and epitaxial compositions along with reproducible characteristics and functional parameters.