Evidence for giant piezoresistance effect in n-type silicon nanowire field-effect transistors

Experimental evidence for the giant piezoresistance (PZR) effect in n-type silicon nanowires (SiNWs) on silicon-on-insulator wafers, also called SiNW field-effect transistors (SiNWFETs), is demonstrated. While an external mechanical strain is applied to SiNWFETs depleted by a back-gate bias, a marked increase in the subthreshold drain current is found, thus supporting the widely reported giant piezoresistance effect. This increase can be attributed to the change in Si/SiO2 interface states, further suggesting interface trap-induced giant piezoresistance. Furthermore, through repeated cycles of tensile and released strain, the electromechanical response of the subthreshold drain current with time offers a potential for creating strain-gated SiNWFETs.