| 摘要 |
PURPOSE: A method for fabricating a semiconductor device having a gate electrode made of polysilicon and germanium is provided to improve the conductivity of the gate electrode and further to prevent variation of a threshold voltage due to boron penetration. CONSTITUTION: After a gate insulating layer(12) is formed on a semiconductor substrate(11), a silicon seed layer(13a) of an amorphous state is formed on the gate insulating layer(12). Next, a polysilicon and germanium layer(14) is deposited on the silicon seed layer(13) and then patterned along with the silicon seed layer(13) to form the gate electrode. Next, impurities for source and drain regions(21a,21b) are implanted, and a resultant structure is then heat-treated. Particularly, in the deposition of the polysilicon and germanium layer(14), polysilicon and germanium are deposited in a crystalline state, and also impurities are in-situ doped thereto. The silicon seed layer(13a) is crystallized through the heat treatment.
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