Impact of Ge implantation on the electrical characteristics of TiSi2 p+/n shallow junctions with an a-Si (or apoly-Si) buffer layer |
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Authors: | Cheng Tung Huang Tan Fu Lei |
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Affiliation: | Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu; |
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Abstract: | A new technology for forming a titanium-silicide shallow junction by combining germanium implantation with an amorphous-silicon (or a poly-silicon) buffer layer has been proposed for MOSFETs. The use of a buffer layer between Ti and Si can avoid the consumption of bulk-silicon and the recession of TiSi2 film into the source/drain junctions during the silicidation process. In this study, the important role of germanium-implantation on the formation of TiSi2 contacted p+/n junctions was examined. After subsequent implantation of Ge+ and B+ into the TiSi2 film, samples were annealed at different temperatures to form p +/n junctions and C54-TiSi2. Since the penetration of titanium atoms was suppressed due to the germanium-implantation, the periphery leakage and the generation leakage were improved and TiSi2/Si interfaces were even smooth. Therefore, p+/n junctions with a very low leakage current (0.192 nA/cm 2 at -5 V) and an excellent forward ideality factor (n≈1.002) can be obtained. From the secondary ion mass spectrometry (SIMS) analysis, the junction depth is 400 |
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