Performance enhancement of GaSb vertical nanowire p-type MOSFETs on Si by rapid thermal annealing

Abstract

GaSb is considered as an attractive p-type channel material for future III-V metal-oxide-semiconductor (MOS) technologies, but the processing conditions to utilize the full device potential such as low power logic applications and RF applications still need attention. In this work, applying rapid thermal annealing (RTA) to nanoscale GaSb vertical nanowire p-type MOS field-effect transistors, we have improved the average peak transconductance (g_m,peak) by 50% among 28 devices and achieved 70μSμm^-1atV_DS = -0.5 V in a device with 200 nm gate length. In addition, a low subthreshold swing down to 144 mV dec^-1as well as an off-current below 5 nAμm^-1which refers to the off-current specification in low-operation-power condition has been obtained. Based on the statistical analysis, the results show a great enhancement in both on- and off-state performance with respect to previous work mainly due to the improved electrostatics and contacts after RTA, leading to a potential in low-power logic applications. We have also examined a short channel device withL_g = 80 nm in RTA, which shows an increasedg_m,peakup to 149μSμm^-1atV_DS = -0.5 V as well as a low on-resistance of 4.7 kΩ·μm. The potential of further enhancement ing_mvia RTA offers a good alternative to obtain high-performance devices for RF applications which have less stringent requirement for off-state performance. Our results indicate that post-fabrication annealing provides a great option to improve the performance of GaSb-based p-type devices with different structures for various applications.

Keywords: GaSb; RTA; p-type MOSFET; performance enhancement; vertical nanowire.