Impact of Substrate Rotation and Temperature on the Mobility and Series Resistance of Triple-Gate SOI nMOSFETs

In this work a comparative experimental analysis of the electron mobility and parasitic source-drain series resistance of triple-gate n-channel MOSFETs as a function of the temperature is carried out. Devices with different fin widths fabricated on standard non-rotated and 45 degrees rotated SOI substrates were analyzed for temperatures ranging from 250 K to 400 K. It is shown that the use of rotated substrate does not affect the subthreshold slope or the threshold voltage variation with temperature of these devices. On the other hand, the change in the conduction plane not only improves the mobility, but also promotes a rise of its variation with temperature. Although the fin width reduction may cause an increase of the series resistance, the increased mobility of rotated devices is responsible for the series resistance roll-off and this reduction becomes larger as the fin is narrowed.