Semiconductor device and its manufacturing method
AssigneeKabushiki Kaisha Toshiba
InventorMikio Wakamiya
Life of this patent
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Abstract
A semiconductor device includes a semiconductor substrate; a gate oxide film made on the semiconductor substrate; and first transistors each having a first gate formed on the gate oxide film and a pair of source/drain formed in confrontation in the semiconductor substrate. The gate oxide film has a higher nitrogen concentration in its portion nearer to the first gates than that of its portion nearer to the semiconductor substrate.
Claims10
A method for manufacturing a semiconductor device including first transistors each having a first gate on a gate insulating film on a semiconductor substrate, in which said gate insulating film is fabricated by a process comprising:
- a first step of making a first oxide film on said semiconductor substrate;
- a second step of making a silicon film on said first oxide film;
- a third step of making a first nitrogen oxide film on said silicon film;
- a fourth step of segregating nitrogen along a surface of said first nitrogen oxide film;
- and
- a fifth step of oxidizing said silicon film to form a second nitrogen oxide film from said first oxide film, said silicon film and said first nitrogen oxide film.
A method for manufacturing a semiconductor device including first transistors each having a first gate on a gate insulating film on a semiconductor substrate, in which said gate insulating film is fabricated by a process comprising:
- a first step of making a first nitrogen oxide film on said semiconductor substrate;
- a second step of making a silicon film on said first nitrogen oxide film;
- a third step of making a second nitrogen oxide film on said silicon film;
- a fourth step of segregating nitrogen along a bottom surface of said first nitrogen oxide film and along a top surface of said second nitrogen oxide film;
- and
- a fifth step of oxidizing said silicon film to form a third nitrogen oxide film from said first nitrogen oxide film, said silicon film and said second nitrogen oxide film.
Dependencies are inferred from the claim text.