Tunable Silicon-Germanium and Silicon Selective Etch in 5-Nanometer and Below Applications

Selective Silicon-Germanium (SiGe) and Silicon (Si) etch chemistries have been developed with emphases on selectivity and enhanced substrate compatibilities. Both acidic- and alkaline-based chemistries have been demonstrated to provide effective selective SiGe etch. Alkaline-based chemistries are also shown to deliver satisfactory selective Si etch vs. SiGe. A unique one-step SiGe and Si dual-etch chemistry with robust substrate compatibility can provide excellent surface roughness and be readily tuned for etch selectivity.