| 摘要 |
The method of the present invention is a method to fabricate a MOS device without boron penetration. After growing a gate oxide layer, a thin stacked-amorphous-silicon layer (SAS) is deposited over the oxide layer. Subsequently, a lightly nitrogen ion is implanted into the stacked-amorphous silicon layer. The stacked-amorphous silicon layer is patterned to define a gate structure. Then, a light doped ion implantation is performed to dope ions through the gate oxide layer into the substrate to form lightly doped source and drain regions. A dielectric layer is formed over the gate structure and the gate oxide layer, and the dielectric layer is etched to form sidewall spacers. Next, a second ion implantation is performed to dope ions into the substrate to form source and drain. Finally, a thermal annealing is performed on the stacked-amorphous silicon gate and the substrate. The nitrogen ions in the stacked-amorphous silicon gate are segregated into the gate oxide layer to act as a diffusive barrier, the stacked-amorphous silicon gate being convert into ploy silicon gate and thereby forming shallow source and drain junction in the substrate.
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