The exponential miniaturization of Si complementary metal-oxide- semiconductor technology has been a key to the electronics revolution. However, the downscaling of the gate length becomes the biggest challenge to maintain higher speed, lower power, and better electrostatic integrity for each following generation. Both industry and academia have been studying new device architectures and materials to address this challenge. In preparation for the 12-nm technology node, this paper assesses the performance of the In 0.75Ga 0.25As of III-V semiconductor compounds and strained-Si channel nanoscale transistors with identical dimensions. The impact of the channel material property and the device architecture on the ultimate performance of ballistic transistors is theoretically analyzed. Two-dimensional and three-dimensional real-space ballistic quantum transport models are employed with band structure nonparabolicity. The simulation results indicate three conclusions: 1) the In 0.75Ga 0.25As FETs do not outperform strained-Si FETs; 2) triple-gate Fin-shaped Field Effect Transistor (FinFET) surely represent the best architecture for sub-15-nm gate contacts, independently from the material choice; and 3) the simulations results further show that the overall device performance is very strongly influenced by the source and drain resistances. © 2012 IEEE.