Investigation on trap density depending on Si ratio in amorphous SiZnSnO thin-film transistors

Abstract

High-performance amorphous SiZnSnO thin-film transistors (a-SZTO TFTs) were fabricated using radio-frequency (RF) magnetron sputtering. The noise spectral density of a-SZTO TFTs measured by using the drain current has been reported, and it was found that is possible to apply the conventional 1/(fa) theory to the lowfrequency noise (LFN) of the a-SZTO TFTs. The LFN characteristics of a-SZTO TFTs can be clearly identified by the correlated number fluctuation-mobility fluctuation model. Based on the noise properties, the interfacial trap density (N-T) was decreased from 2.32 x 10(19) to 1.33 x 10(19) cm(-3) eV(-1) as increasing Si ratio in a-SZTO TFTs. The electrical characteristics and LFN properties of a-SZTO TFTs varied strongly depending on the Si ratio, mainly because the Si atom can act as an oxygen vacancy suppressor.