In this paper we show that on scaling nanowire width from 20 nm down to sub-7 nm regime, together with achieving excellent short channel effect control (DIBL = 12 mV/V for L-G = 20 nm), we hit a dramatic transition in transport mechanism from monotonously increasing I-D-V-G of a FET to oscillating I-D-V-G of a Single Electron Transistor. This transition in transport mechanism is brought about by process induced channel potential variability. It poses a challenge to further scaling of nanowire MOSFETs. However, we show that it provides an exciting opportunity to cointegrate Single Electron Transistors with high-k/metal gate operating at room temperature (at V-D = +/- 0.9 V) with the state-of-the-art nanowire MOSFETs enabling large scale manufacturing of Beyond Moore devices. (C) 2013 Elsevier Ltd. All rights reserved.