Si Industry at a Crossroads: New Materials or New Factories?

Abstract

Many trends in the silicon industry could be interpreted as the herald of the end of traditional Si scaling. If this premise holds, future performance and system-on-chip applications may not be reached with conventional Si technology extensions. We review progress towards our vision that a larger crystal structure on Si, namely relaxed SiGe epitaxial layers, can support many generations of higher performance Si CMOS and new system-on-chip functionality without the expense of significant new equipment and change to CMOS manufacturing ideology. We will review the impact of tensile strained Si layers grown on relaxed SiGe layers. Both NMOS and PMOS exhibit higher carrier mobilities due to the strained Si MOSFET channel. Heterostructure MOSFETs designed on relaxed SiGe can have multiple-generation performance increases, and therefore determine a new performance roadmap for Si CMOS technology, independent of MOSFET gate length. We also indicate that this materials platform naturally leads to incorporating new optical functionality into Si CMOS technology.