Patent ID: 6493256
Filing Date: 2002-12-10
Classification: G11C

Abstract:
A semiconductor memory device having a memory cell storage unit for data storage formed in a semiconductor substrate,said memory cell storage unit comprising: first and second MIS transistors both of a first conductivity type, one electrode of said first MIS transistor and one electrode of said second MIS transistor being commonly connected to a first power supply, the other electrode of said first MIS transistor and the other electrode of said second MIS transistor serving as first and second memory terminals, respectively, said first and second memory terminals being connected to control electrodes of said second and first MIS transistors, respectively, said first and second memory terminals each being set to a first power supply judged-potential that can be judged as a potential on the side of said first power supply when said first and second MIS transistors are in an ON state; and third and fourth MIS transistors both of a second conductivity type, one electrode of said third MIS transistor and one electrode of said fourth MIS transistor being connected to each other, control electrodes of said third and fourth MIS transistors being connected to said first and second memory terminals, respectively, the other electrode of said third MIS transistor and the other electrode of said fourth MIS transistor being independent of said first and second memory terminals, backgate terminals of said third and fourth MIS transistors for setting a substrate potential being connected to a second power supply, wherein said first to fourth MIS transistors are provided so that a potential of said first memory terminal is stable at a second power supply judged-potential that can be judged as a potential on the side of said second power supply when said first MIS transistor is in an OFF state and a potential of said second memory terminal is stable at said second power supply judged-potential when said second MIS transistor is in the OFF state.