Quantitative XPS determination of Pt coverage on SrBi2Ta2O9 thin films forferroelectric memories

X-ray photoelectron spectroscopy measurements were conducted for a spin-coa ted SrBi2Ta2O9 (SBT) system with sputter-deposited 5 nm thick Pt film on it . The spectral peaks were analysed quantitatively under several surface str ucture models. The XPS results also were compared with SEM observation resu lts. The Pt coverage was lowest (similar to 15%) on a specimen prepared fro m complexed alkoxide solution followed by a second annealing at 800 DC in O -2 and sintering in a hydrogen atmosphere at 400 degreesC (H-2 sintering), whereas it was highest (97%) on a specimen prepared from a sol-gel solution without any other treatment except crystallization. From regression analys is of all the data, the effects of the solution property, second annealing and H-2 sintering on Pt coverage were evaluated. It was found that the effe ct of the second annealing in O-2 was very large, whereas that of the H-2 s intering does not give a large effect but it certainly causes a decrease in the apparent Pt coverage. Even the difference in solution for spin-coating has an influence on the Pt coverage, i.e. sol-gel and complex solutions gi ve the highest and lowest values, respectively. It was clarified that the P t-coverage had a clear correlation with fabrication factors, such as soluti on property, second annealing in O-2 and H-2 sintering. There was an excell ent agreement between XPS and SEM results. Copyright (C) 2001 John Wiley & Sons, Ltd.