Semiconductor device and method of manufacturing thereof
AssigneeDenso Corporation
InventorsTakaaki Aoki, Mikimasa Suzuki, Yukio Tsuzuki, Tomofusa Shiga
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Abstract
On the surface of a silicon nitride film, there is formed a thermal oxide film, over which a CVD oxide film is then formed to provide a silicon oxide film of two-layered structure films. Moreover, the total thickness of the two-layered structure films is set to a value from 5 nm to 30 nm. Thus, the silicon oxide film is made into the two-layered structure films of the thermal oxide film and the CVD oxide film to thereby achieve the thickness of the silicon oxide film. As a result, it is possible to prevent a Vth from being lowered by a charge trap phenomenon and to prevent the Vth from fluctuating due to the enlargement of the bird's beak length by the silicon oxide film.
Claims14
A semiconductor device comprising a semiconductor element having an insulated gate structure, in which a gate insulating film having an ONO film comprised of a first silicon oxide film, a silicon nitride film and a second silicon oxide film is formed on the side face of a trench formed on one face of a semiconductor substrate, and in which a gate electrode is formed on the surface of said gate insulating film in said trench, characterized:
- in that said second silicon oxide film comprises a two-layered structure films including:
- a thermal oxide film formed on the surface of said silicon nitride film and a CVD oxide film formed over said thermal oxide film;
- and in that a total thickness of said two-layered structure films is set to a value from 4 nm to 10 nm.
A method for manufacturing a semiconductor device comprising a semiconductor element having an insulated gate structure, in which a gate insulating film having an ONO film composed of a first silicon oxide film, a silicon nitride film and a second silicon oxide film is formed on the side face of a trench formed on one face of a semiconductor substrate, and in which a gate electrode is formed on the surface of said gate insulating film in said trench, characterized:
- in that the step of forming said second silicon oxide film includes:
- the step of forming a thermal oxide film on the surface of said silicon nitride film;
- and the step of forming a CVD oxide film over said thermal oxide film;
- in that said second silicon oxide film is made of two-layered structure films including:
- said thermal oxide film and said CVD oxide film;
- and in that the thicknesses of said thermal oxide film and said CVD oxide film are made such that the total thickness of said two-layered structure films is set to a value from 4 nm to 10 nm.
A method for manufacturing a semiconductor device comprising a semiconductor element having an insulated gate structure, in which a gate insulating film having an ONO film comprised of a first silicon oxide film, a silicon nitride film and a second silicon oxide film is formed on the side face of a trench formed on one face of a semiconductor substrate, and in which a gate electrode is formed on the surface of said gate insulating film in said trench, characterized:
- in that the step of forming said second silicon oxide film includes:
- the step of forming a CVD oxide film on the surface of said silicon nitride film;
- and the step of forming a thermal oxide film over said CVD oxide film;
- in that said second silicon oxide film is made of two-layered structure films including:
- said thermal oxide film and said CVD oxide film;
- and in that the thicknesses of said thermal oxide film and said CVD oxide film are made such that the total thickness of said two-layered structure films is set to a value from 4 nm to 10 nm.
A semiconductor device comprising a semiconductor element having an insulated gate structure in which a gate insulating film having an ONO film including a first silicon oxide film, a silicon nitride film and a second silicon oxide film is formed on the side face of a trench formed on one face of a semiconductor substrate, and in which a gate electrode is formed on the surface of the gate insulating film in the trench, wherein:
- the second silicon oxide film comprises a two-layered film structure including a CVD film formed on the surface of said silicon nitride film and a thermal oxide film formed over said CVD film;
- and a total thickness of said two-layered film structure is set to a value of 4 nm to 10 nm.
Dependencies are inferred from the claim text.