Reducing threshold voltage shifts in amorphous silicon thin film transistors by hydrogenating the gate nitride prior to amorphous silicon deposition

A short H2 plasma treatment of the gate SiNx before depositing amorphous silicon (a-Si:H) is found to significantly decrease the threshold shifts in the bias stress, inverted a-Si:H thin film transistors (TFTs). The reduced threshold voltage shift is attributed to a plasma induced reconstruction of SiNx precursors leading to the removal of the weak bonds. A prolonged plasma treatment, however, degraded the TFT characteristics; this was traced H2 plasma damage which eventually generated a rough a-Si:H/SiNx interface.