High Performance a‐IGZO Thin‐Film Transistors Grown by Atomic Layer Deposition: Cation Combinatorial Approach

Abstract

We report the effect of the cation composition on the electrical performance of amorphous indium gallium zinc oxide (a‐IGZO) thin‐film transistors (TFTs) which was deposited by atomic layer deposition (ALD). The In/In+Ga ratio of a‐IGZO TFT was increased, enhancement of the field‐effect mobility (µFE) value was observed. The device with a higher In/In+Ga ratio: the In0.45Ga0.15Zn0.40O transistor showed a higher µFE value of 48.3 cm2/Vs, VTH of −4.06 V, SS of 0.45 V/decade, and ION/OFF ratio of > 107. Simultaneously, Density of States (DOSs) profile in a forbidden band gap of the a‐IGZO semiconductor were extracted based on the Meyer‐Neldel rule (MN rule) to obtain an insight into the cation composition dependent performance of a‐IGZO TFTs.