NAND flash memory

FIGURE 5.22 (See color insert) Programming operation of a NAND-flash memory-cell, where the programming cell is No. 5 (a) voltage bias conditions for memory cells and (b) parasitic capacitances during No. 5 cell programming. 

Fowler-Nordheim tunneling-current density, well known as the programming mechanism of a NAND-flash memory-cell, is represented by... 

FIGURE 6.2 Technical roadmap for DRAM and NAND flash memory. 

FIGURE 6.8 (a) Cross-sectional SEM image of a 90-nm NAND-flash memory-cell without CMP. (b) Cross-sectional TEM image of a sub-60 nm structure with interpoly ONO dielectrics. 

Recently, flash memory—used in mobile phones, MP3s, digital cameras, and USDs—is a non-volatile memory device that solved a weak point of DRAM device of volatile movement. NAND flash memory in business today is possible up to 2 gigabyte in integrated diagram. It has a characteristic of action at high supply voltage of 10 to 15V. 

New materials are applied to maximize the capacity of device. To increase the capacitance of cap used in DRAM, sfudies about high-k dielectric material are in process. Elash memory uses a gate material with polysilicon by reason of high speed and stable storage. To reduce semiconductor device RC delay, Cu metal lines and low-k are being introduced. This section represents the concept of CMP processing being introduced to DRAM and NAND flash devices. 

Flash memory NAND flash NAND (NOT AND gate) flash memory... 

Flash memory is read and write memory, and data memories do not disappear even through loss of electric power. Therefore, flash memories are widely applied to USB memory, SD memory card, smart media, and compact flash. Flash memory is also applied to hard disks for computers. NAND flash is NAND (NOT AND gate) flash memory. EEPROM is electrically erasable programmable read-only memory, which is called flashed ROM. 

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