An effective electron mobility improvement that uses strain-proximity-free technique (SPFT) has been demonstrated using strain-gate engineering. The electron mobility of nMOSFETs with SPFT exhibits a 15% increase over that of counterpart techniques. The preamorphous layer (PAL) gate structure on the SPFT showed a further performance boost. The electron mobility exhibits a 52% improvement in nMOSFET using a combination of SPFT and PAL gate structure. Furthermore, the gain in electron mobility in the SPFT in combination with PAL gate structure decreases at high temperatures. Gate dielectric interface states and ionized gate impurities inducing carrier scattering will play important roles when operating devices under high-temperature conditions.