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:
Mar. 18, 2003
Filed:
Apr. 09, 2002
Hua Yu Yang, Kaohsiung, TW;
An Min Chiang, Hsin-Chu, TW;
Wei-Kun Yeh, Hsin-Chu, TW;
Chi-Hsiang Lee, Hsin-Chu, TW;
Taiwan Semiconductor Manufacturing Company, Hsin-Chu, TW;
Abstract
A process for reducing the dark current generation of an image sensor cell, fabricated on a semiconductor substrate, has been developed. The process features the use of polysilicon pad structure, formed simultaneously with a polysilicon gate structure of a reset transistor, with the polysilicon pad structure located overlying, and contacting, a portion of the top surface of the photodiode element, of the image sensor cell. A small diameter opening, in a composite polysilicon-silicon oxide layer, exposes the portion of photodiode element to be contacted by the polysilicon pad structure. The small diameter opening is created using a procedure which allows the surface of the photodiode element, exposed in the small diameter opening to experience only a minimum of RIE processing at end point, thus minimizing damage to the surface of the photodiode element, and thus reducing dark current generation. A metal contact structure, used to communicate with the photodiode element, is then formed on the polysilicon pad structure.