Mobility enhancement effect in heavily doped junctionless nanowire silicon-on-insulator metal-oxide-semiconductor field-effect transistors

The effective electron mobility in long-channel silicon-on-insulator junctionless multigate metaloxide-semiconductor transistors is experimentally studied. It is found that the mobility in heavily doped narrow nanowire (NW) devices at low to moderately high carrier densities significantly exceeds that in wide (planar) devices with the same silicon thickness and doping and, in a certain range of carrier densities, it exceeds the mobility in bulk silicon with the same doping concentration. This effect increases when decreasing the NW width. The possible origins of this effect are discussed. These results are extremely encouraging for the development of junctionless NW transistors. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767353]