Challenges of fulfilling the promise of tunnel FETs

III-V Hetero-junction Tunnel FET (HTFET) are promising candidates for supply voltage scaling down to sub-0.5V due to their promise of sub-kT/q switching without compromising on-current (ION). Recently n-type III-V HTFET with reasonable ION and sub-kT/q switching at VDS=0.5V have been demonstrated [1]. However, steep switching performance of III-V HTFET till date has been limited to range of drain current (IDS) spanning over less than a decade. Here, we analyze primary roadblocks in the path towards achieving steep switching performance in III-V HTFET. Temperature dependent current-voltage measurements on III-V HTFET are performed and calibrated numerical simulations are used to quantify the metrics towards realizing sub-kT/q switching over large IDS range.