Array substrate, manufacturing method thereof, and display device

A manufacturing method of an array substrate, comprising:

• forming a first active layer, a material of which is polysilicon;
• injecting ions at least into an area to be doped of the first active layer to form a doped area, which is utilized to be electrically connected to a corresponding source electrode and drain electrode;
• forming a second active layer, a material of which is an amorphous metal oxide, wherein the step of forming the second active layer is performed after forming the first active layer and injecting ions at least into the area to be doped of the first active layer, or is performed before forming the first active layer;
• and
• after injecting ions at least into the area to be doped of the first active layer and forming the second active layer, performing an activation process to activate the ions injected into the first active layer and to convert the material of the second active layer from an amorphous state to a microcrystalline state.