Abstract:
PROBLEM TO BE SOLVED: To provide a nonvolatile memory device in which data stored in a memory cell is associated to whether or not the memory cell is switchable between a first state and a second state. SOLUTION: Memory cells are irreversibly programmed by applying an irreversible programming signal (I IRP ), such that the nonvolatile memory cells (21a) are made not switchable between the first state and the second state. Reading memory cells includes: assessing whether the memory cell (21a, 21b) is switchable between the first state and the second state; determining that the first irreversible logic state "1" is associated to the memory cell 21a, if the memory cell is not switchable between the first state and the second state; and determining that the second irreversible logic value "0" is associated to the memory cell (21b), if the memory cell (21b) is switchable between the first state and the second state. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
METHOD AND DEVICE FOR IRREVERSIBLY PROGRAMMING AND READING NONVOLATILE MEMORY CELLS In a nonvolatile memory device, data stored in a memory cell (21a, 21b) are associated to whether or not the memory cell is switchable between a first state and a second state. Memory cells are irreversibly programmed by applying an irreversible programming signal (I[err]), such that the nonvolatile memory cells (21a) are made not switchable between the first state and the second state in response to the irreversible programming signal (I[err]). Reading memory cells includes: assessing (100, 110, 120, 140, 150, 160) whether a memory cell (21a, 21b) is switchable between a first state and a second state; determining that a first irreversible logic value ("1") is associated to the memory cell (21a), if the memory cell (21a) is not switchable between the first state and the second state (130); and determining that a second irreversible logic value ("0") is associated to the memory cell (21b), if the memory cell (21b) is switchable between the first state and the second state (170).
Abstract:
In a nonvolatile memory device, data stored in a memory cell (21a, 21b) are associated to whether or not the memory cell is switchable between a first state and a second state. Memory cells are irreversibly programmed by applying an irreversible programming signal (I IRP ), such that the nonvolatile memory cells (21a) are made not switchable between the first state and the second state in response to the irreversible programming signal (I IRP ). Reading memory cells includes: assessing (100, 110, 120, 140, 150, 160) whether a memory cell (21a, 21b) is switchable between a first state and a second state; determining that a first irreversible logic value ("1") is associated to the memory cell (21a), if the memory cell (21a) is not switchable between the first state and the second state (130); and determining that a second irreversible logic value ("0") is associated to the memory cell (21b), if the memory cell (21b) is switchable between the first state and the second state (170).
Abstract:
A memory device is proposed. The memory device includes a plurality of memory cells (P,S), wherein each memory cell includes a storage element (P) and a selector (S) for selecting the corresponding storage element during a reading operation or a programming operation. The selector includes a unipolar element (M) and a bipolar element (D;B). The memory device further includes control means (110s) for prevalently enabling the unipolar element during the reading operation or the bipolar element during the programming operation.