The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1994
Filed:
Apr. 02, 1990
Mamoru Tomozane, Scottsdale, AZ (US);
H Ming Liaw, Scottsdale, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A SIMOX structure having a reduced number of defects is formed by performing a two step anneal. In one embodiment, a conventional anneal is followed by an H.sub.2 /Si anneal. The conventional anneal first densifies the buried oxide layer in order to make the oxide less reactive with hydrogen. The H.sub.2 /Si anneal forms a quasi-equilibrium at the superficial semiconductor layer surface, thus there is no etching of the silicon surface and there is only a negligible amount of silicon deposition. The H.sub.2 reacts with the oxide precipitates and dissolves them. In a second embodiment the two step anneal comprises a low temperature H.sub.2 anneal followed by a conventional anneal. At low temperature, H.sub.2 can diffuse through silicon, but is much less reactive. Thus, etching of the superficial silicon and silicon dioxide buried layer is minimal. The conventional anneal is at a higher temperature, thus H.sub.2 can react with the oxygen precipitates to remove them.