Semiconductor–metal phase transition of iron disilicide by laser annealing and its application to form device electrodes

• DOI: 10.1016/j.tsf.2004.02.081
• Publication Date: 2004-07-22T19:46:18Z
• Authors: Naotaka Otogawa; Shinan Wang; Shusaku Kihara; Zhengxin Liu; Yasuhiro Fukuzawa; Yasuhito Suzuki; Masato Osamura; Teruhisa Ootsuka; Takahiro Mise; Kiyoshi Miyake; Yasuhiko Nakayama; Hisao Tanoue; Yunosuke Makita
• Keywords: Ohmic contact

Phase transition of semiconducting β-FeSi2 to metallic α-FeSi2 has been realized by laser annealing (Nd:YAG laser, λ=1.064 μm) in order to form ohmic electrodes for β-FeSi2 devices. The starting samples were 200-nm-thick β-FeSi2 films formed on Si substrates by reactive deposition epitaxy method. XRD and micro-Raman spectroscopy measurements confirmed the successful phase transition. The electrical resistivity of the α-FeSi2 film was 2.0×10−4 Ω·cm, three orders lower than that of the original β-FeSi2 film (1.4×10−1 Ω·cm). Cross-sectional TEM images and electron diffraction patterns indicated that the upper ∼100 nm of the annealed film was changed to α-FeSi2 while the lower part remained to be β-FeSi2. α-FeSi2 layer had good ohmic contact with β-FeSi2. A testing p-β-FeSi2/n-Si diode with laser-annealed α-FeSi2 as the electrode on β-FeSi2 showed the same rectifying characteristic as that using Al-evaporated electrode.