Low Temperature Plasma Process for Si/SiGe Dual Channel Fin Application

In this study, we discuss Si-SiGe etch characteristics as well as SiGe surface composition modification. We found that hydrogen plasma (selective Si etch to SiGe), in combination with conventional plasma etching (selective SiGe etch to Si), controls both Si-SiGe fin etched depth and fin CDs. We could also realize Si-rich surface on SiGe by using a low-temperature plasma process, which can improve SiGe/high-k interface quality in advanced CMOS. The mechanism of the dry etch process and SiGe surface modification will be discussed in this study. (Keywords: Plasma, Dry Etch, Hydrogen and SiGe)