Abstract: The effect of gate-length variation on key transistor metrics for vertical nanowire p-type GaSb metal-oxide-semiconductor field-effect transistors (MOSFETs) are demonstrated using a gate-last process. The new fabrication method enables short gate-lengths (Lg = 40 nm) and allows for selective digital etching of the channel region. Extraction of material properties as well as contact resistance are obtained by systematically varying the gate-length. The fabricated transistors show excellent modulation properties with a maximum Ion/Ioff = 700 (VGS = -0.5,,V) as well as peak transconductance of 50 μS/μm with a linear subthreshold swing of 224 mV/dec.