We fabricate high-k/Ge n-channel metal-insulator-semiconductor field-effect transistors (MISFETs) by the gate-last process with the thermal solid source diffusion to achieve both of high quality source/drain (S/D) and gate stack. The n(+)/p junction formed by solid source diffusion technique of Sb dopant shows the excellent diode characteristics of similar to 1.5 x 10(5) on/off ratio between +1 and -1 V and the quite low reverse current density of similar to 4.1 x 10(-4) A/cm(2) at +1 V after the fabrication of high-k/Ge n-channel MISFETs that enable us to observe well-behaved transistor performances. The extracted electron mobility with the peak of 891 cm(2)/(V.s) is high enough to be superior to the Si universal electron mobility especially in low E(eff). (C) 2010 The Japan Society of Applied Physics