We report the effect of N2 partial pressure on the structure of MgO thin films deposited on Si(100) substrates by radio frequency-magnetron sputtering in Ar+N2 mixture. The films were evaluated using x-ray diffractmeter. As increasing N2 partial pressure, the intensity of (200)MgO reflection increased and saturated above partial pressure of 4.4×10-1 Pa, which corresponds to N2 flow rate of 3 sccm. Effect of N2 gas on the structure of MgO thin films were investigated by plasma emission spectroscopy. The increase of the optical emission intensity of NH spectrum results in the increase of intensity of (200)MgO reflection. We found the strong relationship between the emission intensity of NH spectrum and intensity of (200)MgO reflection. © 1997 American Vacuum Society.