| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable carriers moving in a semiconductor substrate to be improved in mobility. <P>SOLUTION: In a field effect transistor using a gate insulating film of metal oxide or the like, the gate insulating film is a three-layered laminated film composed of a first insulating film formed on a semiconductor substrate, a second insulating film formed on the first insulating film, and a third insulating film formed on the second insulating film. The first insulating film is formed of silicon oxide, silicon nitride, or silicon oxy-nitride, the second insulating film or the third insulating film contains metal. The dielectric constant of the second insulating film is set larger than the square root of the product of the dielectric constant of the first insulating film and the dielectric constant of the third insulating film. By this setup, carriers are less scattered by electric charge present in the gate insulating film or at an interface between the gate insulating film and the semiconductor substrate and improved in mobility, whereby a semiconductor device operating at a high speed can be realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
