| 摘要 |
A semiconductor device is provided to improve the operation characteristic of a device by avoiding out-diffusion of boron to a silicon germanium layer. An active region is defined by an isolation structure(120) included in a semiconductor substrate(110) including an NMOS region and a PMOS region. A gate insulation layer is positioned on the active region in a gate region. A dual poly gate is positioned on the gate insulation layer, including a silicon germanium layer(160). The dual poly gate includes a stack structure of a lower gate electrode(150) and an upper gate electrode(180). The lower gate electrode is composed of an n-type polysilicon layer in the NMOS region and a p-type polysilicon layer in the PMOS region. The upper gate electrode is composed of the silicon germanium layer and a tungsten layer. The silicon germanium layer can have a thickness of 50-150 Å and a germanium density of 0.01-0.6.
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