Carbon nanotube memory cell array program error analysis and tradeoff between reset voltage and verify pulses

Abstract

In emerging non-volatile memories, nano-random access memory (NRAM) has advantages of small program current and high endurance compared with resistive RAM (ReRAM) and phase-change RAM (PRAM). This work comprehensively investigates NRAM set and reset program characteristics by measuring a 116 nm 4 Mbit NRAM cell array. Specifically, reset is found more dependent on reset voltage than reset current. Next, NRAM set and reset bit error rates (BERs) have less significant reduction compared with the increased ratio of set and reset pulse widths. The reset BER can also be reduced by applying multiple reset pulses. Moreover, 108 write cycles are measured on 256 bytes NRAM cells, no wear-out or broken cell is found. Finally, the program characteristics of two verify-reset schemes are compared. The maximum verify-reset voltage can be reduced by increasing the number of reset pulses.

Reset-Check-Reverse-Flag Scheme on NRAM With 50% Bit Error Rate or 35% Parity Overhead and 16% Decoding Latency Reductions for Read-Intensive Storage Class Memory

“…In summary, RCRF recovers only reset error in this case because it is the dominant error in NRAM [22], [33]. On the other hand, though DI cannot correct retention error, it has an advantage of correcting either set error or reset error.…”

Graphene and Related Materials for Resistive Random Access Memories

“…a state change without the application of any electrical stress happens); [2] vi) small size below 600 nm 2 (this refers to the cell that stores 1 bit of information, not the whole NVM); vii) good integration, with a capacity density larger than 10 11 bits/cm 2 ; and viii) simple structure, which usually brings associated low fabrication costs. Several new memory concepts are being developed to achieve these targets, [1][2] including dynamic RAM (DRAM), [11][12] , ferroelectric RAM, [13][14] phase change RAM (PCRAM), [15][16] magnetoresistive RAM (MRAM), [17][18] resistive RAM (RRAM), [19][20] conductive bridge RAM, [21][22] carbon nanotube RAM, [23][24] spin transfer torque magnetic RAM (STTM-RAM), [25][26] molecular memories, [27][28] and Mott memories. [29][30] A comparative review of the different technologies being considered for future information storage can be found in Ref.…”