Characteristics of amorphous In-Ga-Zn-O thin-film-transistors with channel layer deposited by bias sputtering

The influence of substrate bias during sputtering on the amorphous indium-gallium-zinc-oxide (a-IGZO) film and back-channel-etch (BCE) a-IGZO TFT is investigated. A mediated substrate bias is benefit to the improvement of a-IGZO film. The BCE a-IGZO TFT with mediate substrate bias of -90 V exhibits good performances with a field effect mobility (μfe) of 7.45 cm²/V·s, a subthreshold swing (SS) of 0.52 V/Dec and an I_on/I_off current ratio of 10⁹. The gate-bias stress stability is improved by substrate bias with ΔV_th was 1.76 V under PBS and -0.88 V under NBS.