摘要 |
A three-dimensional memory device includes a stack of semiconductor layers. Phase change memory (PCM) cell arrays are formed on each layer. Each PCM cell includes a variable resistor as storage element, the resistance of which varies. On one layer, formed is peripheral circuitry which includes row and column decoders, sense amplifiers and global column selectors to control operation of the memory. Local bit lines and worldliness are connected to the memory cells. The global column selectors select global bitlines to be connected to local bit lines. The row decoder selects wordlines. Applied current flows through the memory cell connected to the selected local bitline and wordline. In write operation, set current or reset current is applied and the variable resistor of the selected PCM cell stores data. In read operation, read current is applied and voltage developed across the variable resistor is compared to a reference voltage to provide as read data.
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