Performance Enhancement of Electrospun IGZO-Nanofiber-Based Field-Effect Transistors with High-k Gate Dielectrics through Microwave Annealing and Postcalcination Oxygen Plasma Treatment

Abstract

We investigated the effects of various high-k gate dielectrics as well as microwave annealing (MWA) calcination and a postcalcination oxygen plasma treatment on the electrical properties and stability of electrospun indium gallium zinc oxide (IGZO)-nanofiber (NF)-based field-effect transistors (FETs). We found that the higher the dielectric constant of the gate dielectric, the better the electric field is transferred, resulting in the better performance of the IGZO NF FET. In addition, the MWA-calcined IGZO NF FET was superior to the conventional furnace annealing-calcined device in terms of the electrical properties of the device and the operation of resistor-loaded inverter, and it was proved that the oxygen plasma treatment further improved the performance. The results of the gate bias temperature stress test confirmed that the MWA calcination process and postcalcination oxygen plasma treatment greatly improved the stability of the IGZO NF FET by reducing the number of defects and charge traps. This verified that the MWA calcination process and oxygen plasma treatment effectively remove the organic solvent and impurities that act as charge traps in the chemical analysis of NF using X-ray photoelectron spectroscopy. Furthermore, it was demonstrated through scanning electron microscopy and ultraviolet-visible spectrophotometer that the MWA calcination process and postcalcination oxygen plasma treatment also improve the morphological and optical properties of IGZO NF.

High-Performance IGZO Nanowire-Based Field-Effect Transistors with Random-Network Channels by Electrospun PVP Nanofiber Template Transfer

“…As an effective method for creating NW-like structures, the electrospinning technology enables the facile fabrication of randomly networked NFs and provides various advantages such as low cost, process simplicity, and large-area manufacturing [ 14 , 15 ]. However, electrospun NFs have issues related to poor electrical properties and reliability owing to the high impurity content induced by the solution-based process [ 16 ]. Furthermore, high-temperature calcination, which is essential for removing the polymer matrix in NFs, makes them unviable for practical flexible electronics applications using thermally vulnerable flexible substrates [ 16 , 17 , 18 ].…”

“…However, electrospun NFs have issues related to poor electrical properties and reliability owing to the high impurity content induced by the solution-based process [ 16 ]. Furthermore, high-temperature calcination, which is essential for removing the polymer matrix in NFs, makes them unviable for practical flexible electronics applications using thermally vulnerable flexible substrates [ 16 , 17 , 18 ].…”