| 摘要 |
The invention provides a method for fabricating ultra-shallow, low resistance junctions. In the preferred embodiment, a nitrogen containing screen oxide layer is formed on an undoped area of a substrate by poly re-oxidation using rapid thermal processing in a nitrogen containing atmosphere. Impurity ions are implanted into the substrate, in the undoped area, through the nitrogen containing screen oxide layer to form lightly doped source and drain regions. A post-implant anneal is performed on the lightly doped source and drain regions using a rapid thermal anneal in a nitrogen containing atmosphere. The nitrogen containing screen oxide layer: prevents surface dopant loss during post implant anneal; prevents gate oxide degradation during ion implantation and screen oxide stripping; and acts as a diffusion barrier, reducing oxygen enhanced diffusion. Alternatively, the poly re-oxidation can be performed in an O2 atmosphere followed by a rapid thermal anneal in a nitrogen containing atmosphere.
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