Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To enable to obtain a semiconductor substrate having few generation of defect improving the element isolation technique by a method wherein a polycrystalline Si layer provided on the semiconductor substrate is oxidized selectively, and after a mask is removed, doping in the polycrystalline Si layer is performed, and after a surface oxide film is formed, the oxide film thereof and a part of the remaining polycrystalline Si layer are removed. CONSTITUTION:The polycrystalline Si layer 13 is provided on the Si substrate 11 interposing an oxide film 12 between them, and after selective etching is performed making the Si3N4 film as a mask to form thick oxide films 16, the Si3N4 mask is removed, then after an impurity is doped in the polycrystalline Si layer to enhance oxidation speed, the thin theral oxide film is formed on the surface, and after then the thermal oxide film is removed and at the same time, oxynitride films 17 are removed, a part of the remained polycrystalline Si layer 13' is removed, and the remained polycrystalline Si layer is oxidized. Accordingly thermal isolation films can be formed reducing generation of defect, and moreover accuracy variation in size cn be reduced.

Inventors

• 👤 Hisahiro Matsukawa
• 👤 Hiroshi Nozawa
• 👤 Junichi Matsunaga

Bibliographic Details