Electron induced secondary electron emission properties of the oxygen-rich aluminum nitride film

In this work, the aluminum nitride (AlN) film was prepared on the stainless steel substrate by radio frequency (RF) magnetron sputtering. The substrate temperature for the preparation of the AlN film with optimal secondary electron emission (SEE) properties was investigated. X-ray diffraction (XRD) spectra revealed that the (100)-oriented AlN films were prepared at the substrate temperature ranging from room temperature to 500 °C. The (100)-oriented AlN exhibited the strongest diffraction intensity at a substrate temperature of 500 °C. X-ray photoelectron spectroscopy (XPS) analysis demonstrated an inverse correlation between deposition temperature and oxygen content in the prepared AlN films. At the substrate temperature of 500 °C, the film attains an Al:N ratio approaching 1:1, indicating optimal nitridation conditions at this temperature. The film achieves a secondary electron yield (SEY) of 4.75 at the incident electron energy of 200 eV that exceeds those of BeO and Al₂O₃ films and maintains superior SEE stability (8.95%/h decay rate) and air stability (4% degradation after 15-day air exposure) outperforming MgO films. The prepared AlN film integrates the high SEY of MgO with the stability of Al₂O₃, qualifying it as a competitive alternative secondary electron emitter material.