Thin-film semiconductor device including a multi-layer channel layer, and method of manufacturing the same

A method of manufacturing a thin-film semiconductor device, comprising:

• preparing a substrate;
• forming a gate electrode above the substrate;
• forming a gate insulating film on the gate electrode;
• forming a channel layer on the gate insulating film, the channel layer being formed of a polycrystalline semiconductor layer;
• forming an amorphous semiconductor layer on the channel layer, the amorphous semiconductor layer having a projecting portion in a surface thereof;
• and
• forming a source electrode and a drain electrode above the amorphous semiconductor layer,
• wherein the amorphous semiconductor layer is formed such that a first portion located closer to the channel layer has a resistivity lower than a resistivity of a second portion located closer to the source electrode and the drain electrode,
• the amorphous semiconductor layer comprises a flat portion and the projecting portion,
• the second portion of the amorphous semiconductor layer comprises a top portion of the projecting portion, and
• the first portion of the amorphous semiconductor layer comprises a lower portion of the projecting portion and the flat portion,
• wherein the projecting portion comprises a single projection, and the flat portion extends laterally from the projecting portion.