RAMAN-SCATTERING IN POLYCRYSTALLINE 3C-SIC - INFLUENCE OF STACKING-FAULTS

We report temperature dependent measurements of the Raman spectra of m icrocrystalline 3C-SiC freestanding films. The measurements were perfo rmed under direct laser heating of the thin films for temperatures up to 1700 K. The temperature dependence of the TO- and LO-phonon frequen cies agrees well with that of single-crystal 3C-SiC, but the Raman lin es are considerably broader. We discuss the influence of stacking faul ts on the linewidth by comparing our results with computer simulated R aman intensity profiles of 3C-SiC structures having randomly distribut ed stacking faults. Good agreement with respect to the linewidth and d isorder-induced peak shift is found if the average stacking fault dist ance is assumed to be 6 Angstrom. We observe an irreversible narrowing of the Raman lines at temperatures above 1900 K, which we ascribe to an annealing of stacking faults in 3C-SiC. [S0163-1829(98)08139-9].