Manufacture of semiconductor substrate

Abstract

Abstract PURPOSE:To easily manufacture an SOI(silicon-on-insulator) substrate whose crystallinity is good and whose area is large by a method wherein a buried silicon oxide layer is formed on the lower side of the bottom of a recessed part formed in a silicon single-crystal substrate and the silicon single-crystal substrate on the lower side of this oxide layer is insulated from other parts and is used as an element formation region. CONSTITUTION:A recessed part 2 is formed on one main face of a silicon single-crystal substrate 1; after that, a first oxygen ion implantation operation and a second oxygen ion implantation operation 3, 4 are executed; after that, a heat treatment is executed; then, a buried silicon oxide layer 5 is formed; silicon-oxide fine protrusions 6 composed of the thick silicon oxide layer are formed at peripheral parts of the bottom. Then, the silicon single-crystal substrate 1 is turned upside down; the rear side of the substrate 1 is polished. When a finish- polishing operation is executed in succession, the silicon-oxide fine protrusions 6 act as a stopper, a silicon single-crystal layer whose thickness is equal to 0.5mum of a protruding portion of the silicon-oxide fine protrusions 6 is formed in an upper layer of the buried silicon oxide layer 6; this layer becomes an element formation region 8. Thereby, it is possible to obtain an SOI substrate which uses, as a main face for element formation use, the rear side of the silicon single-crystal substrate in which a crystal defect is hard to cause even by implanting oxygen ions.

Inventors

• 👤 Fumitoshi Toyokawa
• 👤 豊川　文敏

Bibliographic Details