Metal-oxide-semiconductor (MOS) capacitors incorporating HfO2 and SrHfON gate dielectrics were fabricated by magnetron sputtering. The interface quality, thermal stability, and electrical properties of the MOS capacitors have been investigated. Compared to HfO2 dielectric film, SrHfON dielectric film has thin interface layer with Si substrate, good thermal stability, and low leakage current densities. The dominant current conduction mechanisms (CCMs) of HfO2 film are Schottky emission or Poole-Frenkel emission at low and high electric fields. The main CCMs of SrHfON film are Schottky emission or Poole-Frenkel emission at low electric field, whereas, the CCMs are replaced by space charge limited current at high electric field.