Temperature-dependent Raman scattering in round pit of 4H–SiC

The Raman spectra of N-doped 4H–SiC single crystal films is investigated between 100 and 600 K. The temperature dependence of the three optical modes is obtained. These measurements reveal that all Raman peaks shift to lower frequencies with increasing temperature, except A1(LO). The temperature dependence of A1(LO) phonon modes in the round pit also manifests different features with temperature increasing, but the demarcation temperature point of the blueshift and the redshift in the round pit is higher than that in the outer area. At high temperature, all active phonon modes clearly become broader, but the linewidth of the E1(TO) phonon mode from round pit increases with temperature more rapidly than that from the outer area, this indicates that the lifetime of the E1(TO) phonon in round pit is more sensitive than that in the outer area.

► The temperature dependence of Raman optical modes in round pit of 4H-SiC is obtained.
► A1(LO) tends to blueshift at lower temperature but redshift at higher temperature.
► A1(LO) phonon mode in the round pit has a higher temperature turning point than that in the outer area.
► The linewidth of the E1(TO) mode from the round pit increases with temperature more rapidly than that from the outer area.