| 摘要 |
It is known to provide a reoxidation step in the manufacture of a MOSFET that serves a number of structural purposes in relation to the MOSFET. However, the need to provide materials of high dielectric constant for gate insulator layers of MOSFETs to accommodate a drive for smaller integrated circuits has led to excessive growth of an SiO<SUB>2 </SUB>interfacial layer between the gate insulator layer and a substrate. Excessive growth of the SiO<SUB>2 </SUB>layer results in an Effective Oxide Thickness that leads to increased leakage current in the MOSFET. Further, the replacement of polysilicon with metals as electrodes precludes oxygen exposure during processing. Consequently, the present invention provides replacing or preceding the reoxidation step with the deposition of an oxygen barrier layer over at least side walls of a gate electrode of the MOSFET, thereby providing a barrier for oxygen diffusion to the dielectric interface and metal gate electrode that prevents EOT increase and preserves metal gate electrode integrity.
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