| 摘要 |
PROBLEM TO BE SOLVED: To improve the yield of the source/drain dielectric strength of a transistor by reducing the stresses produced in the circumference of an element isolation region. SOLUTION: A fabrication method for a semiconductor device includes a process (a), in which a 1st oxide film and a 1st silicon nitride film are formed on the surface semiconductor layer of an SOI substrate, a process (b) in which the 1st silicon nitride film is patterned and a 1st LOCOS oxidation is executed by using the patterned 1st silicon nitride film to form a 1st LOCOS oxide film on the part of the surface semiconductor layer, which is to be the element isolation region, a process (c) in which the 1st LOCOS oxide film is selectively removed, a process (d) in which sidewall spacers composed of 2nd silicon nitride films are formed on the sidewalls of the 1st silicon nitride film and the 1st oxide film, a process (e) in which the 2nd LOCOS oxidation is practiced by using the 1st silicon nitride film and the sidewall spacers, to form a 2nd LOCOS oxide film thinner than the 1st LOCOS oxide film and a process (f), in which the 1st and 2nd silicon nitride films are removed.
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