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. 30, 1993
Filed:
Oct. 30, 1990
Robert H Dennard, Peekskill, NY (US);
Nicky C Lu, Yorktown Heights, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Lightly Depleted PMOS (LDP) substrate-plate trench-capacitor (SPT) cell Array architecture is disclosed including three types of devices: An enhancement NMOS transistor (ENMOS) which has a n+ poly gate with a positive threshold voltage range, an enhancement PMOS transistor (EPMOS) having a p+ poly gate with a negative threshold voltage range, and a lightly depleted PMOS transistor (LDPMOS) having a p+ poly gate. The LDPMOS is used as the access transistor in the SPT cell with body biased at the power supply voltage VDD, and can also be used in the write drivers. A sense amplifier is included which is a CMOS cross-coupled latch. An n-well is biased at a lower voltage than VDD, such as (VDD--Vg) where Vg is the silicon bandgap, and the lower thresholds enhance faster sensing. The CMOS cross-coupled latch is activated by turning on latching devices. The bitlines are prevented from charging to greater than VDD--Vg, which could cause the array devices of unselected cells to conduct current and alter the stored low-voltage state of such cells.