Remarkable Effects of Introduction of SiON Materials into Shallow Trench Isolation Fabrication Process on Metal-Oxide-Semiconductor Field-Effect Transistors

概要

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As an advanced fabrication process of fine shallow trench isolation (STI) to preserve sufficient active regions, we investigated the introduction of SiON materials, which are compatible with a well-developed metal-oxide-semiconductor (MOS) process. The use of an SiON sidewall spacer attached to a trench etching hard mask, which makes it possible to form a desirable T-shaped STI configuration, was very effective to remarkably expand the effective channel widths of metal-oxide-semiconductor field-effect transistors (MOSFETs) and to completely suppress field oxide thinning at the trench edges. On the other hand, it was revealed that an SiON liner enveloped at the trench inside suppressed reduction of the effective channel width as well as the concentration of the electric field at the channel edges. These favorable effects, which are brought about by the etching characteristics of the SiON materials, were directly reflected on enhancement of the drivability of the MOSFETs together with improvement of the subthreshold characteristics.
2001-02-15