Preparation And Properties Of CeN Thin Films

In the inertial confinement fusion?ICF?experiment,stimulated scattering due to the laser-plasma interaction?LPI?will cause the loss of laser energy,so the hohlraum wall is the key to reduce energy loss.The researchers found that doping low Z elements into high Z elements as the hohlraum wall can significantly inhibit stimulated Brillouin scattering?SBS?and reduce laser energy loss.In this paper,cerium nitride?CeN?thin films were prepared by DC magnetron sputtering method using metallic cerium as the high Z element and nitrogen as the low Z element.Scanning electron microscope,white-light interferometer,X-ray diffraction and Auger electron spectroscopy were used to study the influence of the preparation process parameters on the deposition rate,surface morphology and internal component structure of CeN thin films.The oxidation mechanism of CeN films was preliminarily explored,and the effect of Al protective layer on the oxidation resistance of CeN films was studied.The main content of this article is as follows:?1?Through the adjustment of the preparation process,the influence on the CeN thin films was studied.1.The study found that the deposition power plays an important role in the deposition rate and quality of the thin film.Control the nitrogen-argon ratio of 1:19 and the working pressure of 0.25 Pa unchanged.When the deposition power is 100 W and 150 W,the CeN films has a clear?111?preferred orientation texture.When the deposition power increases to 200 W and 250 W,the preferred orientation texture disappears,at this time the sample is a mixture of metallic Ce and CeN.2.When the deposition power is 200 W and the working pressure is 0.25 Pa,different ratios of nitrogen and argon have little effect on the surface morphology and surface roughness of the CeN films,but have a greater impact on the structure and deposition rate of the films.With the increase of N₂ flow rate,the CeN films reappears in the?111?plane preferential orientation,and the deposition rate rises.3.The working pressure affects the deposition rate and quality of the film.Control the deposition power of 200 W,the ratio of nitrogen to argon 2:18,when the working pressure is0.4 Pa,the deposition rate of the films is the highest,23.6nm/min,and the XRD half-height width is the smallest,0.196,indicating that the sample has good crystallinity.The working pressure has little effect on the surface morphology and structural composition of the sample.We used magnetron sputtering to produce CeN thin films with a stoichiometric ratio at a deposition power of 200 W,a nitrogen to argon ratio of 2:18,and an operating pressure of0.4 Pa.?2?The oxidation mechanism of CeN thin films was studied.When the CeN films is left in the air for a short period of time,the films will form tiny holes and cracks.When the films is exposed to the atmosphere for 1 day,the films will powder,change from brass color to yellow,and fall off from the substrates.XRD test results show that cerium oxide was formed during the exposure of the film sample to the atmosphere.A detailed analysis of the samples exposed to the atmosphere for 2 hours using Auger electron spectroscopy found that the CeN films before oxidation had a good stoichiometric ratio,and O atoms only appeared in several atomic layers on the surface of the sample.As the oxygen atoms increase,they gradually penetrate into the sample and replace the N atoms in Ce-N to form a Ce-N-O ternary compound.?3?Anti-oxidation study of CeN thin films.A metal aluminum protective layer of tens of nanometers was deposited on the sample surface by magnetron sputtering.AES results show that O atoms are mainly concentrated on the surface of the sample,indicating that the Al protective layer can effectively block oxygen from entering the sample.XRD results showed that the protective layer with a thickness of about 20 nm had a good protective effect within 8 hours,but after 8 hours the samples began to show CeO₂ peaks.When the thickness of the Al layer is increased to 40 nm,the oxidation prevention effect of the sample exceeds 8hours.This thesis systematically studies the influence of the preparation process on the CeN thin films,and explores the rule of DC magnetron sputtering for the preparation of single nitride and the oxidation performance of CeN thin films in air,which not only provides a reference for the selection of the hohlraum wall,but also the follow-up research of CeN film laid the foundation.