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:
Sep. 26, 2000
Filed:
Jun. 28, 1999
Chuan-Fu Wang, San-Chung, TW;
Der-Yuan Wu, Hsin-Chu, TW;
United Microelectronics Corp., Hsin-Chu, TW;
Abstract
The present invention relates to a method of forming a lower electrode of a capacitor on a DRAM cell in a semiconductor wafer for increasing a surface area of the lower electrode. It is achieved by forming a second dielectric layer on a first polysilicon layer which comprises a plurality of doped horizontal layers along a vertical direction. Because dopant densities of the doped horizontal layers alternate in a high and low sequence, when forming a second polysilicon layer on the second dielectric layer, the second polysilicon layer will have many hemispherical grains on the vertical side wall of the second dielectric layer. This will result in an increased surface area of the lower electrode.