Effect of target temperature on microstructure of aluminum surface layer modified by plasma based ion implantation①
(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, P.R.China)
Abstract: Aluminum (99.6% purity) was implanted with nitrogen ions to a total dose of 6×1017cm-2at different temperatures (from 50℃to 400℃) by plasma based ion implantation (PBII). The surface microstructure was investigated by glancing angle X-ray diffraction (GXRD), X-ray photoelectron spectroscopy (XPS) and cross-sectional transmission electron microscopy (XTEM). The results of GXRD and XTEM showed that there was an amorphous layer on the outer surface, and fine dispersion of AlN precipitates was found under the amorphous layer. The size of AlN precipitates strongly depended on the target temperature, with the increase of the target temperature, the size of AlN precipitates became larger. The excess nitrogen atoms can diffuse or migrate to the lower nitrogen concentration regions by radiationenhanced diffusion. The results of XPS further indicated that it was easier to form AlN precipitates at a higher target tem-
perature, and the depth profile of nitrogen broadened.
perature, and the depth profile of nitrogen broadened.
Key words: plasma based ion implantation; aluminum; target temperature; microstructure