Transistor with electrode-protecting insulating film

A semiconductor device comprising:

• a substrate;
• a semiconductor layer formed on the substrate;
• a gate insulating film formed on the semiconductor layer;
• a gate electrode formed in a portion of the area directly above said semiconductor layer on the gate insulating film;
• and
• an electrode-protecting insulating film formed on said gate insulating film and said gate electrode;
• wherein
• a surface layer portion of said electrode-protecting insulating film is etched away after the electrode-protecting insulating film is formed,
• wherein the film thickness of the portion other than the area directly under said gate electrode in said gate insulating film is smaller than the film thickness of the portion positioned in the area directly under said gate electrode, and
• wherein the concentration of metal in the interface between said gate insulating film and said electrode-protecting insulating film is 1×1011 atoms/cm2 or less.

A semiconductor device comprising:

• a substrate;
• a semiconductor layer formed on the substrate;
• a gate insulating film formed on the semiconductor layer;
• a gate electrode formed in a portion of the area directly above said semiconductor layer on the gate insulating film;
• and
• an electrode-protecting insulating film formed on said gate insulating film and said gate electrode;
• wherein
• a surface layer portion of said electrode-protecting insulating film is etched away after the electrode-protecting insulating film is formed,
• wherein the film thickness of the portion other than the area directly under said gate electrode in said gate insulating film is smaller than the film thickness of the portion positioned in the area directly under said gate electrode, and
• wherein a source region, a drain region, and an LDD region are formed in said semiconductor layer, and the ratio (DTr/CLDD) has a value of 0.4 or less, where Dtr is the surface density of carrier traps in the area directly above said LDD region of said gate insulating film, and CLDD is the volumetric concentration of carriers in said LDD region.

A semiconductor device comprising:

• a substrate;
• a semiconductor layer formed in localized fashion on the substrate;
• a gate insulating film formed on the semiconductor layer;
• a gate electrode formed in a portion of the area directly above said semiconductor layer on the gate insulating film;
• and
• an electrode-protecting insulating film formed on said gate insulating film and said gate electrode;
• wherein
• the concentration of metal in the interface between said gate insulating film and said electrode-protecting insulating film is 1×1011 atoms/cm2 or less.

A semiconductor device comprising:

• a substrate;
• a semiconductor layer formed in localized fashion on the substrate;
• a gate insulating film formed on the semiconductor layer;
• and
• a gate electrode formed in a portion of the area directly above said semiconductor layer on the gate insulating film;
• wherein
• a source region, a drain region, and an LDD region are formed in said semiconductor layer;
• and
• the ratio (Dtr/CL,DD) has a value of 0.4 or less, where Dtr is the surface density of carrier traps in the area directly above said LDD region of said gate insulating film, and CLDD is the volumetric concentration of carriers in said LDD region.