Patent ID: 8049275

Claim:
A semiconductor element having a top gate type LDD structure located on a glass substrate, comprising: an upper gate electrode; a lower gate electrode, at least a side thereof on a source electrode side and a drain electrode side protruding from said upper gate electrode, and located in close contact with said upper gate electrode; and a semiconductor section having a channel area directly below said upper gate electrode and said lower gate electrode, an LDD area directly below a protruding portion of said lower gate electrode, and a source area and a drain area not covered with said upper gate electrode and said lower gate electrode, wherein said lower gate electrode comprises a low resistance metal material, wherein said upper gate electrode comprises a high-density metal material or a hydrogen adsorptive metal, and has a high masking ability of hydrogen ions injected during injection of impurities, wherein one of said lower gate electrode and said upper gate electrode comprises tantalum, and wherein a concentration of an impurity added into the LDD area increases from the channel area toward the source area or the drain area.