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. 21, 1999
Filed:
Apr. 18, 1997
Applicant:
Inventor:
Jemmy Wen, Hsinchu, TW;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
257390 ; 257391 ;
Abstract
A method of manufacture for a multiple stage ROM unit capable of coding the multiple stages with a single coding implantation and a method of manufacturing the same. The ROM includes a semiconductor substrate covered by an insulating layer. A gate structure is provided above the insulating layer. A channel region is located on the substrate beneath the gate structure. Source/drain regions are disposed on the semiconductor substrate on each side of the channel region. A cap partially covers the top of the gate structure so as to divide the channel region therebelow into a first channel region and a second channel region such that multiple-level threshold voltages may be coded in the ROM.