Effects of Localized Back-Surface Defects on Bulk and Front-Channel Conduction of Amorphous InGaZnO TFTs.

This paper investigated physical mechanisms underlying the effects of localized back-surface defects ( D\mathrm { {loc}}) on the performances of amorphous InGaZnO thin-film transistors (a-IGZO TFTs). Four bands of density of states were utilized to represent D\mathrm { {loc}} . The a-IGZO thickness ( t\mathrm { {IGZO}}) was varied from 20 to 300 nm. When D\mathrm {{loc}} was absent, the TFT with t\mathrm { {IGZO}} of 20 nm can exhibit the best TFT performance. However, it got the severest performance degradation when D\mathrm {{loc}} was taken into consideration. We further changed acceptor-like tail and deep-level defect states at the back-channel surface from 0 to 10^\mathrm 20 cm ^\mathrm -2 eV ^\mathrm -1 and quantitatively studied their effects on energy band bendings, electric field distributions, carrier concentration distributions, and electrical characteristics of a-IGZO TFTs. [ABSTRACT FROM AUTHOR]