In this paper, we report our work on epitaxial growth of InAlN HEMTs for RF device applications.  InAlN HEMTs were grown on 8” high resistivity silicon substrates. Various characterization techniques were used to analyze the quality of the epi wafers. An average sheet resistance (R_sh) of 206Ω/□, with a uniformity of 1.5% (1s/average), indicated a high quality and uniform 2DEG. Hall measurement showed a high sheet charge density of 2.27×10¹³cm⁻² and a mobility of 1430cm²/(Vs). A pit free epi surface was obtained with optimized growth process of the active layers. T-gate RF devices fabricated on the InAlN epi wafers demonstrated an f_T of 250GHz and an f_MAX of 204 GHz, which are the record high values for GaN-based HEMTs on silicon.