STI Liner Evolution as the CMOS Scaling Down

Abstract

As the planar CMOS transistor devices scaling down, a lot of original process have to be optimized, developed or changed to meet the evolutional requirement, and the new process elements were continuously implemented into the manufacture. The STI-liner is one of the processes from the STI module, which comes after the trench etch and before the trench gap-fill, to provide an excellent interface and good adhesion between the silicon and the oxide. While the device scaling down, some device issues, such as, the incident of dislocations which impacted on the device leakage current, the dopant segregation which result in the threshold voltage variation and impact the inverse narrow width effect (INWE) and the gate oxide integrity (GOI), etc, are associated with the STI module and can be improved by the STI-liner process. The STI liner process is evolved from the furnace oxidation, the dry RTO, the nitrided oxide liner to the ISSG.