Evaluation of the effect of hydrogen plasma treatment on the chemical bonding state and distribution of hydrogen in silicon nitride films by angle-resolved hard X-ray photoelectron spectroscopy

The presence of hydrogen-incorporated defects in silicon nitride (SiN) films has been reported to degrade device properties, such as NAND flash memory. Therefore, controlling the amount of hydrogen defects in SiN films to achieve high device reliability is important. This study investigated hydrogen desorption using hydrogen plasma treatment to reduce hydrogen-incorporated defects in SiN films. Secondary ion mass spectrometry measurements showed that the hydrogen concentration in SiN films does not change significantly pre- and post-treatment. However, the trap levels in SiN films determined using the Poole-Frenkel analysis of hole currents showed a clear deepening after the plasma treatment. Angle-resolved hard X-ray photoelectron spectroscopy measurements suggested that hydrogen plasma treatment decreases the ratio of silicon to hydrogen or nitrogen to hydrogen bonds as a function of treatment time.