Hydrogenated amorphous silicon thin-film transistor using APC alloy for both gate and data bus lines

We demonstrated a hydrogenated amorphous silicon thin-film transistor (TFT) using an APC (Ag-Pd-Cu) alloy for both gate and data bus lines. The APC alloy has lower resistivity than those of pure Al and Al alloys, but it has unstable properties such as poor adhesion and being damaged by plasma during PECVD and dry etching process. To solve this problem, we used thin buffer layers such as Al₂O₃, AlN, and Mo beneath or above APC. By adding these layers efficiently, we could improve adhesion and obtain good reliability in the plasma process. An a-Si:H TFT with an APC alloy exhibited a field-effect mobility of 0.88 cm²/V s, a gate voltage swing of 0.87 V/dec. and a threshold voltage of 4.5 V.