Engineered substrates and their future role in microelectronics

Progress in lattice engineering, planar ultra-strained epitaxial layer growth, and layer transfer technology has resulted in the ability to create many engineered substrate types. In particular, a wealth of possibilities exists in the SiGe/Si system. Engineered substrates based on relaxed SiGe layers on Si with strained Si and Ge layers have resulted in long channel MOSFETs with ∼2× enhancement in NMOS drive current and more than 10× enhancement in PMOS drive current as compared to control Si MOSFETs. We have attempted to increase the NMOS drive current further by beginning to explore strained GaAs on relaxed SiGe layers on Si.