Electronic transport properties of silicon junctionless nanowire transistors fabricated by femtosecond laser direct writing

Silicon junctionless nanowire transistor (JNT) is fabricated by femtosecond laser direct writing on a heavily n-doped SOI substrate. The performances of the transistor, i.e., current drive, threshold voltage, subthreshold swing (SS), and electron mobility are evaluated. The device shows good gate control ability and low-temperature instability in a temperature range from 10 K to 300 K. The drain currents increasing by steps with the gate voltage are clearly observed from 10 K to 50 K, which is attributed to the electron transport through one-dimensional (1D) subbands formed in the nanowire. Besides, the device exhibits a better low-field electron mobility of 290 cm²·V^-1·s^-1, implying that the silicon nanowires fabricated by femtosecond laser have good electrical properties. This approach provides a potential application for nanoscale device patterning.