Interface state density measurements in gated p-i-n silicon nanowires as a function of the nanowire diameter

Gate-all-around p-i-n silicon nanowires (NW) diodes with effective nanowire diameter from 15 nm down to 4 nm (±1.3 nm) were fabricated to enable interface state density (Nit) measurements using the charge pumping (CP) method. The Nit of the NWs was also measured by the conductance method and was in good agreement with the CP method. The linear relation between the CP current and the pulse frequency was not maintained in the smallest diameter NWs. The dependency on the pulse rise and fall times was also investigated and is correlated to the lifetime of the traps. The impact of the cylindrical geometry on the measured CP current is discussed.