Oxide thin film transistor, manufacturing method thereof, array substrate and display device

An array substrate, comprising an oxide thin film transistor (Oxide TFT), the Oxide TFT comprising:

• a base substrate;
• a gate electrode, a gate insulating layer and an active layer that are on the base substrate;
• a source electrode and a drain electrode, the active layer being at least partly covered with the source electrode and the drain electrode;
• and
• a channel protection layer between the source electrode and the drain electrode, each of the source electrode and the drain electrode comprising at least part of a first metallic layer and at least part of a second metallic layer, the first metallic and the second metallic layer being stacked one on another, and
• the channel protection layer being of a metal oxide.

A manufacturing method of an Oxide TFT, comprising:

• providing a base substrate;
• sequentially forming a gate electrode, a gate insulating layer and an active layer on the base substrate;
• sequentially forming a first metallic layer and a second metallic layer on the active layer;
• performing a patterning process to the second metallic layer to form a source electrode and a drain electrode;
• and
• performing an oxidation treatment to a part of the first metallic layer between the source electrode and the drain electrode, so as to form a channel protection layer, during the patterning process of forming the source electrode and the drain electrode.