  Diamond and Silicon Carbide (SiC) are promising wide band-gap semiconductors
for power electronics, SiC being more mature especially in term of large wafer
size (that has reached 200 mm quite recently). Nitrogen impurities are often
used in both materials for different purpose: increase the diamond growth rate
or induce n-type conductivity in SiC. The determination of the nitrogen content
by secondary ion mass spectrometry (SIMS) is a difficult task mainly because
nitrogen is an atmospheric element for which direct monitoring of N$^\pm$ ions
give no or a weak signal. With our standard diamond SIMS conditions, we
investigate 12C14N-secondary ions under cesium primary ions by applying high
mass resolution settings. Nitrogen depth-profiling of diamond and SiC (multi-)
layers is then possible over several micrometer thick over reasonable time
analysis duration. In a simple way and without notably modifying our usual
analysis process, we found a nitrogen detection limit of $2\times 10^{17}$
at/cm$^3$ in diamond and $5\times10^{15}$ at/cm$^3$ in SiC.
