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:
Jan. 04, 1977
Filed:
Feb. 28, 1975
Juergen Graul, Gruenwald, DT;
Helmuth Murrmann, Ottobrunn, DT;
Siemens Aktiengesellschaft, Berlin & Munich, DT;
Abstract
A ring or lattice-shaped groove or trench is etched into a surface of a Si monocrystal layer. At least one boundary of the so-etched groove or trench is coated with a strip-shaped layer of an oxidation-blocking material, such as Si.sub.3 N.sub.4 and the area of the substrate adjacent to the Si.sub.3 N.sub.4 layer and/or the substrate area enclosed by such layer is provided with a relatively thick SiO.sub.2 layer which extends deeper into the Si surface than does the SiN.sub.4 layer, while the Si surface within the groove or trench remains uncoated. The so-obtained arrangement is then thermally oxidized under conditions sufficient to at least partially fill the groove or trench with SiO.sub.2. Thereafter, the oxidation-blocking layer and at least a part of the SiO.sub.2 layer which is outside the ring or lattice-shaped trench is removed by a suitable etchant from the monocrystalline surface and the thus uncovered Si surface is further processed to produce small pn-junctions.