Patent ID: 7923779

Claim:
A semiconductor element having a top gate type LDD structure located on a substrate, comprising: a lower gate electrode on a gate insulating film, having a top surface and side surfaces; an upper gate electrode being in contact with the top surface and side surfaces of the lower gate electrode and with the gate insulating film, at least a side thereof on a source electrode side and a drain electrode side protruding from said lower gate electrode, wherein a portion of the upper gate electrode over the lower gate electrode has a first upper surface and a portion of the upper gate electrode which protrudes from said lower gate electrode has a second upper surface, and the first upper surface is located at a higher level from the gate insulating film than the second upper surface; 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 upper electrode, and a source area and a drain area not covered with said upper gate electrode and said lower electrode, wherein said lower gate electrode comprises a low resistance metal material; and wherein said upper gate electrode comprises a high-density metal material having a density of at least 8 or a hydrogen adsorptive metal, and has a high masking ability of hydrogen ions injected during injection of impurities.