METHOD OF MANUFACTURING THIN FILM TRANSISTOR

PROBLEM TO BE SOLVED: To solve such a problem of a thin film transistor where a contact layer consisting of microcrystalline semiconductor is provided between the source/drain electrode and an active layer that irregularities are formed on the surface of the contact layer which is formed by the direct deposit method, an off-leak current is generated because the film thickness of a recess becomes thin, and thereby the electrical properties degrade, meantime, an area where the irregularities on the surface of the contact layer cannot be covered with the active layer 5 occurs when deposition is carried out until a film thickness required for the recess in the contact layer to suppress the off-leak current is attained, and that area becomes the resistance when an on-current flows.SOLUTION: After deposition is carried out until a film thickness sufficient for the recess in the contact layer 4 to suppress the off-leak current is attained, its surface is planarized to form an active layer. Consequently, the surface of the contact layer 4 can be covered with the active layer 5 substantially uniformly, and since the off-leak current is reduced, a TFT having the characteristics of large on-current can be obtained.