Semiconductor device and method of manufacturing the same
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasao Inoue
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Abstract
A polycrystalline silicon film is formed on a surface of a trench and on a surface of a silicon nitride film. A silicon substrate covered with a polycrystalline silicon film is thermally oxidized at 900 to 1100° C. in an oxygen ambient to provide an uneven interface between a thermally oxidized silicon film and the silicon substrate. Thus a semiconductor device can be obtained capable of reducing a compressive stress caused in the semiconductor substrate near an element isolating trench region to minimize formation of crystal defect.
Claims6
A semiconductor device manufacturing method of forming an element isolating trench region electrically isolating an element forming region formed at a main surface of a silicon semiconductor substrate from another element forming region formed at a main surface of said semiconductor substrate;
- comprising:
- the step of forming a trench in a main surface of said semiconductor substrate;
- and
- an interface formation step subjecting a main surface of said semiconductor substrate in said trench to a first thermal oxidation process to form a first oxide film and also partially enhancing thermal oxidation of a surface of said semiconductor substrate associated with said first thermal oxidation process to allow said first oxide film and said semiconductor substrate to have an uneven interface therebetween, wherein said interface formation step is followed by the steps of:
- removing said first oxide film to expose an uneven surface of said semiconductor substrate in said trench;
- and
- subjecting said uneven surface of said semiconductor substrate to a second thermal oxidation process to form a second thermal oxide film.
Dependencies are inferred from the claim text.