Synthesis of magnesium nitride films with BN as protective layers by reactive radio-frequency magnetron sputtering

Magnesium nitride films were synthesized on silicon substrates by reactive radio-frequency magnetron sputtering (13.56 MHz) with a high-purity magnesium target and nitrogen as the working gas. The effects of the sputtering power and the growth temperature on the qualifies of Mg3N2 films were investigated. As for Mg3N2 films synthesized at 773 K for 2 h with the sputtering power of 200 W, the intense Raman peak at 381 cm(-1) with the Full width at half maximum of 8.3 cm(-1) and the sharp X-Ray Diffraction peak of Mg3N2 (222) at 20 = 31.1 degrees were observed, and the ultraviolet-visible absorption spectra showed that the prepared Mg3N2 films have the intrinsic absorption edges of about 480 nm and the optical bandgap of 2.62 eV. Moreover, it was demonstrated that Boron nitride films can be used as not only protective layers to effectively prevent Mg3N2 films from being hydrolyzed, but also good optical windows.