Method of manufacturing semiconductor device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTamotsu Ogata
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Abstract
A thin gate insulating film of a transistor in a core circuit region is formed with a three-layer structure having an oxide film formed by thermally oxidizing a main surface of a semiconductor substrate (silicon substrate), a CVD nitride film formed on the oxide film and oxynitride film formed by oxidizing the upper surface of the CVD oxide film. A thick gate insulating film of a transistor in an I/O circuit region is formed with a pure oxide film. As a result, such a semiconductor device is obtained in that NBTI of the transistor in the I/O circuit region can be reduced, reliability of the gate insulating film can be improved while a threshold voltage of the transistor in the core circuit region can be properly controlled, and NBTI of the transistor in the core circuit region can be reduced.
Claims4
A method of manufacturing a semiconductor device including a dual oxide process forming a thin gate insulating film for a transistor included in a first circuit region and a thick gate insulating film for a transistor included in a second circuit region having a thickness larger than that of the thin gate insulating film on the same semiconductor substrate, wherein
- in said first circuit region a transistor is formed including a thin gate insulating film having a two-layer structure including an oxide film and a CVD nitride film formed in this order on said semiconductor substrate, and in said second circuit region a transistor is formed having a drive voltage higher than that of the transistor in said first circuit region and including a thick gate insulating film having a pure oxide film with a thickness larger than that of said thin gate insulating film.
Dependencies are inferred from the claim text.