In this letter, we show that conventional III–V MOSFETs with moderate/high In content channels (In0.53Ga0.47As or In0.70Ga0.30As) at scaled nodes are incompatible with mobile SoC designs, which often operate at intermediate/high ${V_{{\mathrm {dd}}}}$ (0.7 V to $\geq 1$ V) to achieve high frequency including during burst-mode. The incompatibility is due to conventional III–V FETs having too small bandgap, and thus too high leakage when operated at the increased voltages. We show that FETs with a more optimal lower In content, In0.35Ga0.65As, have the necessary combination of larger bandgap (~Si) and sufficiently high injection velocity (~2.5 times Si) to enable both low leakage and high performance (versus Si), across the entire ${V_{{\mathrm {dd}}}}$ range of mobile SoC operation. We report for the first time the growth and characterization of ultra-thin In0.35Ga0.65As FETs with a standard 1nm EOT gate dielectric. Calibrated models show that In0.35Ga0.65As enables the highest performance at very low leakages at intermediate/high ${V_{{\mathrm {dd}}}}$ in short channel FETs.