N-type 4H-SiC crystals are studied by Hall effect and Raman spectroscopy. The transport parameters, n and mu, Obtained by both procedures are compared for a series of samples with different nitrogen concentrations. A good agreement between both is obtained. A Raman study in the temperature range between 300 and 650 K is also carried out, the temperature dependence of phonon parameters and plasmons is reported, and the results are compared with high temperature Hall effect measurements.