Flash memory: Difference between revisions

Revision as of 22:02, 24 October 2005

Revision as of 14:54, 25 October 2005

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==Overview==

Normal EEPROM only allows one ___location at a time to be erased or written, meaning that. flashFlash memory can thus operate at higher effective speeds when the system usesarchitecture itallows tomultiple read and writereads to differenttake locationsplace atsimultaneous thewith samethat time.one Allwrite types of flash memory and EEPROM wear out after(to a certaindifferent number of erase operations, due to wear on the insulating oxide layer around the charge storage mechanism used to store data___location). A typical NOR flash memory unit wears out after 10,000-100,000 erase/write operations, a typical NAND flash memory after 1 million.

Flash memory is made in two forms: [[Nor|NOR]] flash and [[Nand|NAND]] flash. The names refer to the type of [[logic gate]] used in each storage cell. Both types of flash memory and EEPROM wear out after many erase operations, due to wear on the insulating oxide layer around the charge storage mechanism used to store data. A typical NOR flash memory unit wears out after 10,000-100,000 erase/write operations, a typical NAND flash memory after 1,000,000.

Flash memory is non-volatile, which means that it stores information on a silicon chip in a way that does not need power to maintain the information in the chip. In addition, flash memory offers fast read access times and solid-state shock resistance. These characteristics explain the popularity of flash memory for applications such as storage on battery-powered devices like [[mobile phone]]s and [[personal digital assistant]]s.

Flash memory is non-volatile, which means that it stores information on a silicon chip in a way that does not need power to maintain the information stored in the chip. In addition, flash memory offers fast read access times (though not as fast as volatile DRAM memory used for main memory in PCs) and solid-state shock resistance. These characteristics explain the popularity of flash memory for applications such as storage on battery-powered devices like [[mobile phone]]s and [[personal digital assistant]]s.

Flash memory is based on the Floating-Gate Avalanche-Injection Metal Oxide Semiconductor (FAMOS) transistor, which is essentially an [[NMOS]] transistor with an additional conductor suspended between the gate and source/drain terminals.

Flash memory is essentially an [[NMOS]] transistor with an additional conductor suspended between the gate and source/drain terminals. This variation is called the Floating-Gate Avalanche-Injection Metal Oxide Semiconductor (FAMOS) transistor.

Flash memory is made in two forms: [[Nor|NOR]] flash and [[Nand|NAND]] flash. The names refer to the type of [[logic gate]] used in each storage cell.

==Principles of operation==