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:
Dec. 04, 2001
Filed:
Aug. 27, 1998
Claudio Brambilla, Concorezzo, IT;
Valerio Cassio, Polonghera, IT;
Paolo Caprara, Milan, IT;
Manlio Sergio Creda, Lomagna, IT;
STMicroelectronics S.r.l., Agrate Brianza, IT;
Abstract
A method of manufacturing a semiconductor virtual ground memory device having a matrix of floating gate memory cells formed on a semiconductor substrate with a plurality of continuous bit lines extending across the substrate as discrete parallel stripes. The device also includes a circuit portion for selection transistors and decode and address circuit portions having P-channel and N-channel MOS transistors. According to the method, N-wells are formed in at least one substrate portion to accommodate the P-channel transistors, active areas of all transistors are defined using a screening mask, and then an isolation layer is grown through the apertures of the screening mask. The screening mask is not open over the matrix region of the memory cells.