With the gate length of MOSFETs approaching 10 nm, the channel region contains only one or a few dopant atoms. Thus, the number and position of dopant atoms become critical factors in determining device performance. In previous work, we have revealed that the control of not only the dopant atom number but also its position is essential by experimentally for the first time . A several theoretical analyses of random dopant fluctuation (RDF) effects have been presented since 1990s [2,3,4]. However, the effect of individual dopant positions on device electrical properties is not well understood experimentally. Here, we report the fabrication of transistors whose channel dopants are implanted one by one using single-ion implantation (SII) method [5,6,7]. Electrical measurements reveal that controlling of discrete dopant position serves to highlight the improvements in device transconductance.