This paper discusses the historical role that SiGe has played in driving the CMOS scaling roadmap, including discussion of NMOS biaxial strain and PMOS uniaxial strain. The paper also discusses the potential future role that Ge or SiGe may play in CMOS scaling as a high mobility replacement for the Si channel. Challenges such as poor quality germanium oxide and the small Ge bandgap are reviewed in light of recent developments (high-k metal gate, and ultra-thin body devices) in MOSFET scaling.