| 摘要 |
A method for manufacturing a semiconductor device is provided to control characteristic degradation problem of a threshold voltage and a driving current due to a gate depletion by forming an SiGe layer whose boron solubility is higher than a poly silicon layer at each edge of a p+ poly silicon layer. A semiconductor substrate(300) having a P-well(302a) and an N-well(302b) is provided. A gate oxide layer(310) is formed on the semiconductor substrate. A non-doped poly silicon layer is formed on the gate oxide layer. N-type impurities are selectively implanted into the non-doped poly silicon layer part formed on the P-well. P-type impurities are selectively implanted into the non-doped poly silicon layer part formed on the N-well. A metal layer(330) and a hard mask nitride layer(340) are formed in turn on the resultant structure. The hard mask nitride layer, the metal layer, the poly silicon layer, and the gate oxide layer are etched in turn to form an n-type gate(350a) on the P-well and a p-type gate(350b) on the N-well. Ge is selectively ion-implanted into both sidewalls of the p-type gate to form an SiGe layer(325) at each edge of the poly silicon layer of the p-type gate.
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