EPROM | EEPROM | Flash EPROM |
Normalize cell size is 1. | Normalize cell size is about 1 to 1.2. | Normalize cell size is about 3. |
EPROM stands from Erasable Programmable Read-Only Memory. | EEPROM stands for Electrically Erasble Programmable Read-Only Memory. | Flash memory is a special type of EEPROM. |
Programming mechanism is hot electron injection. | Programming mechanism is hot electron injection. | Programming mechanism is tunneling. |
Programming time is less than 100 micro second. | Programming time is less than 100 micro second. | Programming time is less than 5 millisecond. |
Erasing machanism is Ultraviolet light. | Erasing mechanism is tunneling. | Erasing mechanism is tunneling. |
Erase time is 20 minutes. | Erase time is 1 second. | Erase time is 5 millisecond. |
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Flash memory:
Flash memory is a special type of EEPROM. Flash memory is a non-volatile memory. In flash memory single cell can be electrically programmed. And whole chip or block can be electrically erased. Flash memory uses a hybrid of EPROM and EEPROM. Flash memories are useful in portable applications. Flash memory cell consists of storage transistor, a control gate, and floating gate, which is insulated by a dielectric material. NAND flash memory and NOR flash memory are the two types of flash memory.