Passivation of Amorphous Oxide Semiconductors Utilizing a Zinc–Tin–Silicon–Oxide Barrier Layer

Abstract

Sputter-deposited amorphous zinc-tin-silicon-oxide (ZTSO) is demonstrated to be a viable electronic passivation layer for bottom-gate thin-film transistors (TFTs) with amorphous zinc-tin-oxide and indium-gallium-zinc-oxide channels. ZTSO allows for successful passivation of these semiconductors without significant changes in turn-on voltage, hysteresis, or channel mobility that is commonly associated with unsuccessful passivation of amorphous oxide semiconductors (AOSs). Passivation of AOS TFTs using ZTSO significantly increases electrical stability under negative-bias illumination stress testing conditions compared with unpassivated AOS TFTs. ZTSO also acts as a barrier layer allowing for additional postprocessing (e.g., plasma-enhanced chemical vapor deposition processes) that in some cases can negatively effect an unprotected AOS layer.