Characterization of electron mobility in ultrathin body germanium-on-insulator metal-insulator-semiconductor field-effect transistors

We have systematically investigated electron mobility behaviors in germanium-on-insulator (GeOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) with reducing the Ge channel thickness down to 9 nm. 9 nm-thick GeOI n-MOSFETs operated with a reasonable I-on/I-off ratio of similar to 10(5), but it showed the electron mobility degradation compared with thick GeOI case. To investigate the physical origin of the mobility degradation in ultrathin body (UTB) GeOI n-MOSFETs, the depth profiling of GeOI crystallinity was investigated by Raman spectroscopy. A difference of Ge crystallinity in the front channel from that in back one was discussed to explain the mobility degradation in UTB region. (C) 2013 AIP Publishing LLC.