This paper employs micro-Raman technique for detailed analysis of the defects

(both inside and outside) in bulk 4H-SiC. The main peaks of the first-order Raman

spectrum obtained in the centre of defect agree well with those of perfect bulk 4HSiC,

which indicate that there was no parasitic polytype in the round pit and the

hexagonal defect. Four electronic Raman scattering peaks from nitrogen defect

levels were observed in the round pit (395, 526, 572 and 635/s), but could not be

found in the spectra of hexagonal defect. The theoretical analysis of the

longitudinal optical plasmon—phonon coupled mode line shape indicates the nonuniformity

of nitrogen distribution between the hexagonal defect and the outer area

in 4H-SiC. The second-order Raman features of the defects in bulk 4H-SiC were

well-defined using the selection rules for second-order scattering in wurtzite

structure and compared with that in the free defect zone.

Raman Analysis of Defects in n-Type 4H-SiC. Y.T.Yang, R.Han, P.Ru, P.Wang:

Chinese Physics B, 2008, 17[9], 3459-63