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:
Oct. 09, 2001
Filed:
May. 07, 1998
Mitsuhiro Horikawa, Tokyo, JP;
Masahito Watanabe, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A semiconductor substrate is provided which maintains its gettering capabilities throughout the manufacturing process of a semiconductor device and which prevents previously gettered contaminating impurities from being released again into an operating region of a semiconductor device. The semiconductor substrate includes a silicon substrate, a polysilicon layer, and a high density boron layer. The silicon substrate has a first main surface and a second main surface opposed to the first main surface, and the silicon substrate is used to form a semiconductor device at least indirectly on the first main surface. The polysilicon film is formed at least indirectly on the second main surface, and the high density boron layer is disposed between the silicon substrate and the polysilicon film. Also a ratio of a highest boron density value in the high density boron layer to a lowest boron density value in the silicon substrate is greater than or equal to approximately 100. Instead of using the high density boron layer, other layers may be used such as silicon oxide layers or polysilicon layers. Also, a method for manufacturing the semiconductor substrate is also provided.