Figure high-resolution B 1s XPS spectra from the BN films deposited on Sample 1, 2, and 3 following 700 s Ar + sputter-cleaning. For all investigated samples, the B 1s spectra present a peak centered around 190.2-190.6 eV, corresponding to B-N bonding . These peaks show that BN has nucleated on Sample 1, 2, and 3. This is supported from high-resolution N 1s XPS spectra, not shown, with single peaks positioned at 397.8 eV from N-B bonding . In addition, the presence of π-plasmon peak from B support sp 2 -hybridization in Sample 1 and 2. Sample 3 displays additional peaks with one peak at 188.0 eV and a doublet peak 178.5 eV and 180.9 eV. The peaks originate from B-Zr bonding as determined from B1s photoelectrons at 188.0 eV and from Zr3d photoelectrons at 179.1 eV and 181.4 eV, respectively. The binding energies of the peaks agrees with those previously determined by Tengdelius et al. for an epitaxial ZrB2 film deposited on a 4H-SiC(0001) substrate . The appearance of these peaks in the spectrum suggests that the BN film on Sample 3 has been partly sputtered through. For Sample 3 there is an apparent shift of the π-plasmon peak towards higher energy that is due to the presence of the bulk plasmon peak of ZrB2. In addition, XPS was applied for quantitative analysis of the deposited BN film, see Table . From the determined compositions it is evident that all the deposited films are boron rich and with the highest B/N ratio of 1.30 determined for Sample 1 followed Sample 2 with 1.25, and finally Sample 3 with 1.20. Thus, Sample 1, 2 and 3 show decreasing B/N ratio, while Sample 3 exhibit a slightly higher nitrogen content.