Raman Investigation of SiC Polytypes

TLDR

Raman scattering spectroscopy is a powerful non‑destructive tool for characterizing SiC crystals. This review surveys recent advances in using Raman scattering to probe the structural and electronic properties of SiC crystals. The article discusses Raman‑based techniques for polytype identification, defect and stress analysis, and electronic transitions—including plasmon‑LO phonon coupling, anisotropic carrier dynamics, semiconductor‑to‑metal transitions, and Fano interference—in SiC crystals.

Abstract

It has been recognized that Raman scattering spectroscopy is a powerful tool to characterize SiC crystals non-destructively. We review recent significant developments in the use of Raman scattering to study structural and electronic properties of SiC crystals. The areas to be discussed in the first part include polytype identification, evaluation of stacking disorder and ion-implantation damages, and stress evaluation. The Raman scattering by electronic transitions is discussed in the second part of this article. We concentrate on the plasmon LO-phonon coupled modes whose spectral profiles are used to evaluate the carrier concentration and mobility. Anisotropic electronic properties of α-SiC and characteristics of heavily doped crystals are discussed. Semiconductor-to-metal transition and Fano interference effect are also treated.