| 摘要 |
PURPOSE:To sufficiently inject electrons into a floating gate from an FLOTOX- type EEPROM even when a Vcc for a DRAM cannot be set to be large and to enhance the reliability of the title programming method in an NVDRAM which is formed on the FLOTOXtype EEPROM. CONSTITUTION:Electric charges stored in a floating gate for an EEPROM are erased; in succession, a source, a recall gate and a select gate are set to a GND; a pulse at a programming voltage Vpp is applied to a control gate; a piece of data '0' or '1' is stored in the floating gate. In succession, the control gate and the source are set to the GND; the pulse at the programming voltage Vpp is applied to the recall gate, the select gate and a drain; a write promotion process is performed. Thereby, in a memory cell into which electrons have been injected, at least a voltage having the portion of a Vth for a memory cell transistor is applied to a storage node and the Vth is raised. |
