Figure 1. Material quality of epitaxial SiC layers grown with brominated chemistry. (a) Typical LTPL spectra of layers grown with C/Si = 1 and Si/ H2 = 0.30% using chlorinated (Cl/Si = 4, growth rate 120 μm/h) and brominated chemistries (Br/Si = 4, growth rate 130 μm/h), as indicated for each spectrum. The spectra are completely dominated by the free-exciton phonon replicas, some of which are denoted in a common notation by I and a subscript indicating the energy of the phonon (in meV) involved in the recombination. The inset displays the same spectra in the whole spectral region measured; the weak peak at ∼4880 Å is the second order of the exciting laser line (244 nm) scattered from the sample. The residual n-type doping estimated from the LTPL measurement is 9 × 10 13  cm −3  for the chlorinated chemistry and 1 × 10 14  cm −3  for the brominated chemistry. (b) HRXRD ω-scans of the 4H-SiC(0004) XRD peak of a bare substrate and a 23 μm thick epitaxial layer grown at 90 μm/h. The fwhm is 7 arcsec for the epitaxial layer. An X-ray slit opening of 5 × 5 mm 2 , corresponding to a footprint of ∼5 × 16 mm 2  for the 4H-SiC(0004) peak, was used.