Effects of random number and location of the nanosized metal grains on the threshold voltage variability of silicon gate-all-around nanowiren-type metal-oxide-semiconductor field-effect transistors

In this study, the effect of the metal grain number (MGN) and metal grain location (MGL) with a low/high work function (WK) on the variability of the threshold voltage (sigma V-th) of silicon gate-all-around nanowiren-type metal-oxide-semiconductor field-effect transistors was examined by using an experimentally validated cuboid grain method. For the effect of the MGN,sigma V(th)induced by WK fluctuations strongly depended on the MGN for the same metal-gate area. For the effect of the MGL, metal grains with a low WK near the source (S) side are crucial for the magnitude of sigma V-th. Therefore, for the weighted superposition of the WK with each metal grain, the number of metal grains with a low WK near theSside may alter the distribution ofV(th)and dominate the magnitude of sigma V-th.