Regular Papers
Reduction of Surface Cracks in β-FeSi2 Films by Substrate Heating during RF-Sputtering Deposition
2013 年 38 巻 2 号 p. 243-247
詳細
2013 年 38 巻 2 号 p. 243-247
FeSix films were deposited on Si(100) substrates at room temperature and at temperatures in the range of 100-300°C using RF-sputtering method with an FeSi3 target. After deposition, FeSix films were annealed at 400-900°C for 10 min in Ar gas. The crystal quality of the films was analyzed by X-ray diffraction (XRD) measurements, the surface of β-FeSi2 films was observed by an optical microscope and the film thickness was measured by surface step-measuring microscope. For the films deposited at 300°C and annealed over 800°C, Si(111) peak at 28.4° was superimposed on the β-FeSi2 (202/220) peak, which indicates that the films contained silicon crystals. On the other hand, for the films deposited at room temperature, Si(111) peak at 28.4° was not observed. No cracks were observed after annealing on the surface of the films deposited at 300°C although the films deposited at room temperature had cracks on the surfaces after annealing over 700°C. The major factor of cracks is considered to be the difference of the expansion coefficients between β-FeSi2 and silicon. For the film deposited at 300°C, a layer containing silicon crystals was formed near Si substrates. This layer served as a buffer between β-FeSi2 and silicon.
