Simulation of non-volatile memory cell using chalcogenide glasses

2012 ◽  
Vol 536 ◽  
pp. S516-S521 ◽  
Author(s):  
J. Rocca ◽  
M. Fontana ◽  
B. Arcondo
2006 ◽  
Vol 918 ◽  
Author(s):  
Semyon D. Savransky ◽  
Eugenio F. Prokhorov

AbstractInitial attempts to create memory from chalcogenide glasses (g-Ch) had limited success particularly because the first generation of these materials (labeled as CG1) has inferior endurance (about 106 SET-RESET cycles). Recent progress in phase-change non-volatile memory (PC-RAM) related to superior properties of Ge2Sb2Te5 (GST) alloy [1,2]. The paper answers the vital for PC-RAM development question: “Why is endurance of GST memory cells (about 1011 cycles) much higher than of CG1 cells?” We show that superior endurance is related to features of –U centers [3] creation in GST during RESET of PC-RAM cells. The native –U centers exist in g-Ch due to the softness of atomic potentials [3]. They play a significant role in SET process of CG1 and GST [2,4]. The –U centers behavior in GST [5] is different compared with CG1 while other properties (threshold voltage, resistivity, etc.) are basically the same [1-4]. We found that dielectric permittivities e of CG1 and GST are also different.The e values in Ge-Sb-Te alloys films have been determined from impedance measurements in sandwich samples using method described in [6] and reported in the paper. Amorphous GST has relatively high and distinct static and optical dielectric permittivities eo=16.5 and e'=15.3 to compare with CG1 where e practically independent on frequency. Hence the second term in the effective polarization potential Ep = q^2[(1-1/e')/r + (1/e' - 1/eo)/L] is strong (here r and L are the average atomic radius and interatomic bond distance, q is the electron charge). It allows to screen the Coulomb repulsion at an –U center quite effectively in GST. Therefore polarization helps –U centers creation in amorphous GST and impedes these centers formation in crystalline hexagonal GST films where eo=38 and e'=61. In contrast to CG1 [3], the creation and destruction of –U centers during RESET and SET processes in GST [4] are not accompanied by strong plastic mechanical stresses in a memory cell. This feature (higher barrier between elastic and plastic deformations) predetermines possibility of numerous SET-RESET cycles in this alloy. Therefore, the deformation mechanism of –U centers formation in CG1 leads to inferior endurance while the polarization mechanism of their creation in GST ensures decent endurance. Second factor is hybritization of –U centers with extended states can also play role in good memory alloys. Obtained experimental e values in non-stochiometric films allow to conclude about expected endurance in the framework of the proposed model.


2020 ◽  
Vol 29 (01n04) ◽  
pp. 2040001
Author(s):  
N. R. Butterfield ◽  
R. Mays ◽  
B. Khan ◽  
R. Gudlavalleti ◽  
F. C. Jain

This paper presents the theory, fabrication and experimental testing results for a multiple state Non-Volatile Memory (NVM), comprised of hafnium oxide high-k dielectric tunnel and gate barriers as well as a Silicon Quantum Dot Superlattice (QDSL) implemented for the floating gate and inversion channel (QDG) and (QDC) respectively. With the conclusion of Moore’s Law for conventional transistor fabrication, regarding the minimum gate size, current efforts in memory cell research and development are focused on bridging the gap between the conventions of the past sixty years and the future of computing. One method of continuing the increasing chip density is to create multistate devices capable of storing and processing additional logic states beyond 1 and 0. Replacing the silicon nitride floating gate of a conventional Flash NVM with QDSL gives rise to minibands that result in greater control over charge levels stored in the QDG and additional intermediate states. Utilizing Hot Carrier Injection (HCI) programming, for the realized device, various magnitudes of gate voltage pulses demonstrated the ability to accurately control the charge levels stored in the QDG. This corresponds to multiple threshold voltage shifts allowing detection of multiple states during read operations.


2008 ◽  
Vol 55 (8) ◽  
pp. 2202-2211
Author(s):  
Wen-Jer Tsai ◽  
Tien-Fan Ou ◽  
Hsuan-Ling Kao ◽  
Erh-Kun Lai ◽  
Jyun-Siang Huang ◽  
...  

2022 ◽  
Vol 27 (2) ◽  
pp. 1-18
Author(s):  
Shaahin Angizi ◽  
Navid Khoshavi ◽  
Andrew Marshall ◽  
Peter Dowben ◽  
Deliang Fan

Magneto-Electric FET ( MEFET ) is a recently developed post-CMOS FET, which offers intriguing characteristics for high-speed and low-power design in both logic and memory applications. In this article, we present MeF-RAM , a non-volatile cache memory design based on 2-Transistor-1-MEFET ( 2T1M ) memory bit-cell with separate read and write paths. We show that with proper co-design across MEFET device, memory cell circuit, and array architecture, MeF-RAM is a promising candidate for fast non-volatile memory ( NVM ). To evaluate its cache performance in the memory system, we, for the first time, build a device-to-architecture cross-layer evaluation framework to quantitatively analyze and benchmark the MeF-RAM design with other memory technologies, including both volatile memory (i.e., SRAM, eDRAM) and other popular non-volatile emerging memory (i.e., ReRAM, STT-MRAM, and SOT-MRAM). The experiment results for the PARSEC benchmark suite indicate that, as an L2 cache memory, MeF-RAM reduces Energy Area Latency ( EAT ) product on average by ~98% and ~70% compared with typical 6T-SRAM and 2T1R SOT-MRAM counterparts, respectively.


2018 ◽  
Vol 88-90 ◽  
pp. 169-172
Author(s):  
S. Xu ◽  
H. Wang ◽  
J. Wu ◽  
L. Zheng ◽  
J. Diao

2004 ◽  
Vol 830 ◽  
Author(s):  
Albert Fazio

ABSTRACTIt expected that for many years to come, the majority of the nonvolatile memories shipped will be based on current mainstream flash technologies, which utilize transistor based charge storage memory cells and multi-level-cell concepts, for storing more than one logic bit in a single physical cell. Moore's law will continue to drive transistor based memory technology scaling but technology complexity will be increasing. In order to meet technology scaling, the mainstream transistor based flash technologies will start evolving to incorporate material and structural innovations. This paper will review the current status and discuss the approaches being explored to provide scaling solutions for future transistor based non-volatile memory products. Based on the introduction of material innovations, it is expected that the planar transistor based flash memory cell can scale into the 32nm node. Further, more complex, structural innovations will be required to maintain further scaling. New memory concepts, not relying on transistors as a basis of the memory cell, provide new opportunities for future low cost memories. Several of these new concepts will be summarized and contrasted with the mainstream transistor based flash memory technologies.


2006 ◽  
Vol 53 (6) ◽  
pp. 3195-3202 ◽  
Author(s):  
Andrea Cester ◽  
Alberto Gasperin ◽  
Nicola Wrachien ◽  
Alessandro Paccagnella ◽  
Valentina Ancarani ◽  
...  

2005 ◽  
Vol 351 (21-23) ◽  
pp. 1873-1877 ◽  
Author(s):  
V. Bouquet ◽  
P. Canet ◽  
F. Lalande ◽  
R. Bouchakour ◽  
J.M. Mirabel

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