Comparative Study on Performance of IGZO Transistors With Sputtered and Atomic Layer Deposited Channel Layer

Abstract

The structural, chemical, and electrical properties of amorphous indium gallium zinc oxide (a-IGZO) films by magnetron sputtering and atomic layer deposition (ALD) were investigated where both a-IGZO films had a comparable cation composition. The ALD-derived a-IGZO film exhibited the higher atomic packing density, the effective suppression of trap-like oxygen vacancy defect (VO), and the enhancement in the hybridization of the sp orbital of In, Ga, and Zn cations compared to those of the sputtered a-IGZO film. Hence, a significant improvement in terms of the field-effect mobility was observed for the thin-film transistors with an In0.50Ga0.34Zn0.16O channel by ALD (36.6 cm(2)/V.s) compared to that of the sputtered In0.48Ga0.38Zn0.14O transistor (20.1 cm(2)/V.s); the I-ON/OFF ratios for both were similar to 10(7). Simultaneously, the gate bias stress stability and photobias stress stability were also improved for the IGZO transistors with an ALD-derived channel, which can be explained by its reduced trap-like VO density.