Effect of the spin-on-glass curing atmosphere on In–Ga–Zn–O thin-film transistors

Abstract

A solution-based spin-on glass (SOG) was applied to the gate insulator of an oxide thin-film transistor (TFT). The curing atmosphere of the SOG was investigated to enhance the performance of the self-aligned top-gate In–Ga–Zn–O (IGZO) TFT. After the SOG layer was formed on an IGZO active layer, curing was performed under N2, air, and O2 atmospheres. The curing under an N2 atmosphere resulted in the best device characteristics for the IGZO TFT. After curing, the SOG films were investigated via atomic force microscopy, secondary ion mass spectroscopy, Fourier transform infrared spectroscopy, and capacitance measurement. The results showed that the N2 pile-up at the back surface of the SOG is the main reason for the enhanced performance of the TFT after curing under an N2 atmosphere.

Keywords

• thin-film transistors
• oxide semiconductor
• spin-on glass
• gate insulator
• curing atmosphere