High-Performance Gate-First Epitaxial Ge n-MOSFETs on Si With LaAlO3 Gate Dielectrics

Abstract

This brief presents high-performance Ge n-MOSFETs with good high-field mobility of 218 cm(2)/V . s at 0.5 MV/cm, low subthreshold swing (SS) of 108 mV/dec, small equivalent oxide thickness (EOT) of 1.6 nm, low 7 x 10(-10) A/mu m OFF-state leakage, small bias temperature instability of 31 mV at 1.2 V overdrive and 85 degrees C, and full process compatibility with current very large-scale integration fabrication. These are one of the best SS and high-field mobility data among gate-first Ge n-MOSFETs using epitaxial Ge on 6-in Si wafer and proper high-kappa LaAlO3 dielectric without using an interfacial layer. Using a different high-kappa HfAlO gate dielectric, the Ge n-MOSFETs showed poor leakage, large flatband voltage shift, and degraded EOT.