The impacts of zero-temperature-coefficient (ZTC) points of various strained devices is presented in this paper. The current and mobility are reduced at high temperature by phonon scattering. The degree of mobility reduction becomes severe on devices with multiple strain-gate engineering. The reduction of mobility becomes severe as a result of impurity scattering, which results from gate implantation impurities. The ZTC point is decreased by multiple strain-gate engineering due to the decreased Vth.