| 摘要 |
An embodiment of the invention provides a germanium-based NMOS device and a method for fabricating the same, which relates to fabrication process technology of an ultra-large-scale-integrated (ULSI) circuit. The germanium-based NMOS device has two dielectric layer interposed between a metal source/drain and a substrate. The bottom dielectric layer includes a dielectric material having a high pinning coefficient S such as hafnium oxide, silicon nitride, hafnium silicon oxide or the like, and the top dielectric layer includes a dielectric material having a low conduction band offset &Dgr;EC such as titanium oxide, gallium oxide, strontium titanium oxide or the like. According to the method, Fermi level pinning effect can be alleviated, electron barrier height can be lowered, and thus performance of the germanium-based Schottky NMOS device can be improved. Compared with a conventional single dielectric layer such as aluminum oxide (Al2O3), Schottky barrier height can be lowered while low source/drain resistances can be maintained, and thus performance of the device can be significantly improved. |
