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:
Feb. 25, 2003
Filed:
Mar. 28, 2001
Toshio Yoshida, Sakurai, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A high-concentration light-receiving N-layer is formed by ion implantation in a region near a substrate surface, and a low-concentration N-type epitaxial layer is formed by epitaxial growth in a deeper region. The depletion layer of a photodiode is thus expanded to a deep portion of the substrate by the low-concentration N-type region , by which a photoelectric conversion effect on incident light of a long wavelength is increased to improve sensitivity. In the above stage, a deepest potential portion is formed on the substrate surface side. Therefore, a depletion voltage can be prevented from rising. Further, an intermediate-concentration N-type epitaxial layer and a high-concentration N-type epitaxial layer are formed in a stack of two layers by epitaxial growth in a region deeper than a region in which a first P-type layer , or a barrier region is formed, by which a shutter voltage can be prevented from rising. Thus, sensitivity is improved without causing a rise in the depletion voltage and shutter voltage.