Method for producing an active matrix substrate

A method for producing an active matrix substrate which uses a thin transistor layer having a semiconductor layer having a contact region and a channel region, a gate insulating layer, a gate electrode formed on a substrate in this sequence, a source electrode and a drain electrode each kept in contact with the contact region, the source electrode and the drain electrode partly overlapping with end portions of the semiconductor layer which end portions are wider than the gate insulating layer and the gate electrode, the gate insulating layer having declined sides wherein the sides thereof adjacent the gate electrode form a narrower top surface than a bottom surface thereof toward the substrate, and wherein ions are implanted into the semiconductor layer from the gate electrode such that a contact layer is formed in a portion of the semiconductor layer overlapping with at least part of the declining sides of the gate insulating layer and part of the semiconductor layer extending beyond the gate insulating layer.