Method for manufacturing self-aligned thin film transistor

The invention discloses a method for manufacturing a self-aligned metal oxide thin film transistor. The method comprises the following steps of: generating an active layer with high carrier concentration; and performing oxidation treatment on a channel region which is self-aligned with a gate electrode through a plasma with an oxidation function; thus, the manufactured transistor has a self-aligned structure while a source region and a drain region have high carrier concentration and the channel region has low carrier concentration; in addition, threshold value voltage of the transistor is controlled by a plasma treatment condition with the oxidation function at a subsequent low temperature; therefore, the controllability of characteristics of the transistor is greatly improved, and a manufacturing process flow is also simplified.