Masahiro Kamoshida

Random telegraph noise in flash memories - model and technology scaling

This paper presents the first statistical model of Vt fluctuation (ΔVt_cell) in a floating-gate flash memory due to random telegraph noise. It considers current-path percolation, which generates a large-amplitude-noise tail, caused by dopant induced surface potential non-uniformity It concludes that the impact of scaling is weaker than the widely-accepted 1/L_effW_eff trend. 3-σ ΔVt_cell is estimated to increase by 1.8x rather than ≫10x from 90 nm to 20 nm technology nodes.

A 32-Mb chain FeRAM with segment/stitch array architecture

A 96mm/sup 2/, 32Mb chain FeRAM in 0.20/spl mu/m 3M CMOS and stacked capacitor technology is described. Cell efficiency of 65.6% is realized by compact memory cell structure and segment/stitch WL architecture. The word line power-on/off sequence protects the data from startup noise. A 3/spl mu/A standby current bias generator and compatible access mode SRAM are implemented for mobile applications.

A 76 mm/sup 2/ 8 Mb chain ferroelectric memory

An 8 Mb chain FeRAM uses 0.25 /spl mu/m 2-metal CMOS technology. A one-pitch-shift cell realizes 5.2 /spl mu/m/sup 2/ cell area. A chain architecture with a hierarchical wordline scheme gives 76 mm/sup 2/ die. Random access time is 40 ns, and cycle time is 70 ns at 3.0 V.

7.1 A low-power 64Gb MLC NAND-flash memory in 15nm CMOS technology

The demand for high-throughput NAND Flash memory systems for mobile applications such as smart phones, tablets, and laptop PCs with solid-state drives (SSDs) has been growing recently. To obtain higher throughput, systems employ multiple NAND Flash memories operating simultaneously in parallel. The available power for a mobile device is severely restricted and the peak total operating current may be high enough to cause large supply-voltage drop or even an unexpected system shutdown. Therefore it is important for NAND Flash memories to reduce operating power and peak operating current.

A Low Power 64 Gb MLC NAND-Flash Memory in 15 nm CMOS Technology

A 75 mm2 low power 64 Gb MLC NAND flash memory capable of 30 MB/s program throughput and 533 MB/s data transfer rate at 1.8 V supply voltage is developed in 15 nm CMOS technology. 36% power reduction from 3.3 V design is achieved by a new pumping scheme. New low current peak features reduce a multi-die concurrent programming peak by 65% for 4-die case, and an erase verifying peak by 40%, respectively. Nanoscale transistors reducing bit-line discharge time by 70% is introduced to improve performance.