Impact of an Interfacial Layer on the Electrical Performance of p-Channel Tin Monoxide Field-Effect Transistors

Abstract

This study examined the insertion effect of an interfacial, 7-nm-thick SiNx and SiOF layer on the performance of p-channel tin monoxide (SnO) fieldeffect transistors (FETs). The control SnO FETs, which had a thermal SiO2 gate dielectric, exhibited a mobility, gate swing, threshold voltage (V-TH) and I-ON/OFF ratio of 2.8 cm(2) V(-1)s(-1), 6.9 V decade(-1), 19.0 V, and 1.8 x 10(3), respectively. The SiNx-inserted SnO FETs showed a loss in drain current modulation due to the creation of interfacial trap states. In contrast, the gate swing and VTH values were improved substantially to 5.4 V decade(-1) and 2.0 V for the SiOF-inserted SnO FETs, respectively, whereas the comparable mobility and ION/OFF ratio were preserved. The rationale of the improvement is discussed with respect to Fermi-energy pinning based on the valence band spectra.