THIN FILM TRANSISTOR

摘要

Provided is a thin film transistor which has an oxide semiconductor layer that has good mobility, excellent stress resistance and good wet etching characteristics. This thin film transistor comprises, on a substrate, at least a gate electrode, a gate insulating film, an oxide semiconductor layer, a source/drain electrode and a protective film, sequentially in this order. The oxide semiconductor layer is a laminate that comprises a first oxide semiconductor layer (IGZTO) and a second oxide semiconductor layer (IZTO). The second oxide semiconductor layer is formed on the gate insulating film, and the first oxide semiconductor layer is formed between the second oxide semiconductor layer and the protective film. The contents of respective metal elements relative to the total amount of all the metal elements excluding oxygen in the first oxide semiconductor layer are as follows: the Ga content is 5% or more; the In content is 25% or less (excluding 0%); the Zn content is 35-65%; and the Sn content is 8-30%.