Reactively-sputtered AlOx passivation layer for self-aligned top-gate amorphous InGaZnO thin-film transistors

Abstract

The direct-current reactive sputtering of aluminum oxide (AlOx) films with Al target was investigated to provide a preferable passivation layer (PL) for self-aligned top-gate (SATG) amorphous metal oxide semiconductor (AOS) like amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs). The grown AlOx films exhibited excellent electrical characteristics, with major parameters including a relative dielectric constant around 9, breakdown electric field of 3.7 MV/cm, and leakage current of 6.29 × 10−8 A/cm2 at 2 MV/cm. It is shown that the AlOx PL, together with a PECVD SiO2 interlayer could provide SATG a-IGZO TFTs with trustworthy environmental and electrical stability.