Interface studies of N-2 plasma-treated ZnSnO nanowire transistors using low-frequency noise measurements
Date of this Version8-2-2013
Due to the large surface-to-volume ratio of nanowires, the quality of nanowire-insulator interfaces as well as the nanowire surface characteristics significantly influence the electrical characteristics of nanowire transistors (NWTs). To improve the electrical characteristics by doping or post-processing, it is important to evaluate the interface characteristics and stability of NWTs. In this study, we have synthesized ZnSnO (ZTO) nanowires using the chemical vapor deposition method, characterized the composition of ZTO nanowires using x-ray photoelectron spectroscopy, and fabricated ZTO NWTs. We have characterized the current-voltage characteristics and low-frequency noise of ZTO NWTs in order to investigate the effects of interface states on subthreshold slope (SS) and the noise before and after N-2 plasma treatments. The as-fabricated device exhibited a SS of 0.29 V/dec and Hooge parameter of similar to 1.20 x 10(-2). Upon N-2 plasma treatment with N-2 gas flow rate of 40 sccm (20 sccm), the SS improved to 0.12 V/dec (0.21 V/dec) and the Hooge parameter decreased to similar to 4.99 x 10(-3) (8.14 x 10(-3)). The interface trap densities inferred from both SS and low-frequency noise decrease upon plasma treatment, with the highest flow rate yielding the smallest trap density. These results demonstrate that the N-2 plasma treatment decreases the interface trap states and defects on ZTO nanowires, thereby enabling the fabrication of high-quality nanowire interfaces.
Nanoscience and Nanotechnology