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. 02, 2001
Filed:
Feb. 23, 1998
Robert Daniel McGrath, Andover, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
An improved pixel design for a CMOS image sensor with a small feature size is described. In conventional image sensors of this type, the quantum efficiency is typically reduced as a result of the decreased thickness of the top n-type layer of the photodiode and the presence of an intervening p-type layer which is higher doped than the substrate. In the pixel design of the invention, the higher doped p-type layer underneath the photodiode is omitted while barrier regions channel the carriers generated by the impinging radiation towards the top n-layer of the photodiode. A high quantum efficiency is thereby attained in spite of a shrinking feature size. The novel pixel design can also incorporate anti-blooming protection.