Highly Selective Si vs. SiGe and SiGe vs. Ge Wet Etch for Sub 2nm Applications

Selective Silicon (Si) and Silicon-Germanium (SiGe) etch chemistries have been developed to provide superior Si vs. SiGe and SiGe vs. Ge etch selectivity up to 1,000 or more. Unique etch differentiators demonstrate preferential etch suppressions of SiGe or Ge respectively. Another oxidative alkaline chemistry provides simultaneous Si and SiGe FinFET fin trimming in the range of 0.75-0.90. Their etch mechanisms and substrate compatibility are discussed.