Simulation of impurities with an attractive potential in fully 3-D real-space Non-Equilibrium Green’s Function quantum transport simulations

The impact of one unintentional channel dopant on the performance of an n-channel Si nanowire MOSFET has been investigated using 3D non-equilibrium Greenpsilas function simulations. Both donors and acceptors have been studied. The attractive donor potential is screened by conducting electrons through resonant states. The resultant inverted-sombrero potential has a twofold effect: lowering of the source-drain barrier and creating resonant states in the potential well, both of which increase the current. At low gate voltage the donor induced current increases two orders of magnitude compared to the impurity-free device. At high gate voltage, the current difference slowly disappears. In the case of an acceptor in the channel the current is reduced over the whole gate bias range.