Semiconductor device having a gate insulating film structure including an insulating film containing metal, silicon and oxygen and manufacturing method thereof

A semiconductor device comprising:

• a semiconductor substrate, and
• first and second transistor regions formed on said semiconductor substrate, each of said first and second transistor regions having a gate insulating film at least a part of said gate insulating film including a metal oxide film;
• wherein an insulating film containing metal, silicon and oxygen is formed between said semiconductor substrate and said metal oxide film, said insulating film provided in one of the first and second transistor regions contains fluorine or fluorine and nitrogen;
• and
• wherein a metal element constituting said insulating film containing metal, silicon and oxygen in one of said first and second regions is different from that of the metal oxide film and the composition rations of the metal elements, silicon and oxygen of said insulating films in said first and second regions are different from each other.

A semiconductor device comprising:

• a semiconductor substrate;
• a first transistor region on said semiconductor substrate, in which a first metal oxide film is provided as at least part of a first gate insulating film and a first insulating film containing metal, silicon and oxygen is provided between the semiconductor substrate and the first metal oxide film;
• and
• a second transistor region on said semiconductor substrate, in which a second metal oxide film is provided as at least part of a second gate insulating film and a second insulating film containing metal, silicon and oxygen is provided between the semiconductor substrate and the second metal oxide film, and a part of at least one of said first and second gate insulating films adjacent to the semiconductor substrate contains fluorine or fluorine and nitrogen;
• wherein a metal element constituting the first or second metal oxide film in said first or second transistor region and that in the corresponding first or second insulating film are different from each other.