Effect of fabrication process on hysteresis of carbon nanotube FETs

Carbon nanotube field effect transistors (CNTFETs) have great advantages over the conventional Si MOSFETs because of their high transconductance and large current driving capability. However, CNTFETs exhibit a large hysteresis in the I_D-V_GS characteristics. W. Kim et al. have reported that the water molecules on the device surface are the origin of the large hysteresis, which can be suppressed by surface passivation using PMMA. In our experiments, however, the reproducibility was quite poor. In this study, we have statistically studied the hysteresis and the passivation process. The reproducibility of the passivation has been improved by introducing cleaning process before the PMMA passivation.