scholarly journals Van der Waals engineering of ferroelectric heterostructures for long-retention memory

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Chao Zhu ◽  
Ya Deng ◽  
Ruihuan Duan ◽  
Jieqiong Chen ◽  
...  

AbstractThe limited memory retention for a ferroelectric field-effect transistor has prevented the commercialization of its nonvolatile memory potential using the commercially available ferroelectrics. Here, we show a long-retention ferroelectric transistor memory cell featuring a metal-ferroelectric-metal-insulator-semiconductor architecture built from all van der Waals single crystals. Our device exhibits 17 mV dec−1 operation, a memory window larger than 3.8 V, and program/erase ratio greater than 107. Thanks to the trap-free interfaces and the minimized depolarization effects via van der Waals engineering, more than 104 cycles endurance, a 10-year memory retention and sub-5 μs program/erase speed are achieved. A single pulse as short as 100 ns is enough for polarization reversal, and a 4-bit/cell operation of a van der Waals ferroelectric transistor is demonstrated under a 100 ns pulse train. These device characteristics suggest that van der Waals engineering is a promising direction to improve ferroelectronic memory performance and reliability for future applications.

2021 ◽  
Vol 11 (2) ◽  
pp. 261
Author(s):  
Frank J. van Schalkwijk ◽  
Walter R. Gruber ◽  
Laurie A. Miller ◽  
Eugen Trinka ◽  
Yvonne Höller

Memory complaints are frequently reported by patients with epilepsy and are associated with seizure occurrence. Yet, the direct effects of seizures on memory retention are difficult to assess given their unpredictability. Furthermore, previous investigations have predominantly assessed declarative memory. This study evaluated within-subject effects of seizure occurrence on retention and consolidation of a procedural motor sequence learning task in patients with epilepsy undergoing continuous monitoring for five consecutive days. Of the total sample of patients considered for analyses (N = 53, Mage = 32.92 ± 13.80 y, range = 18–66 y; 43% male), 15 patients experienced seizures and were used for within-patient analyses. Within-patient contrasts showed general improvements over seizure-free (day + night) and seizure-affected retention periods. Yet, exploratory within-subject contrasts for patients diagnosed with temporal lobe epilepsy (n = 10) showed that only seizure-free retention periods resulted in significant improvements, as no performance changes were observed following seizure-affected retention. These results indicate general performance improvements and offline consolidation of procedural memory during the day and night. Furthermore, these results suggest the relevance of healthy temporal lobe functioning for successful consolidation of procedural information, as well as the importance of seizure control for effective retention and consolidation of procedural memory.


2012 ◽  
Vol 52 (8) ◽  
pp. 1627-1631 ◽  
Author(s):  
Jer-Chyi Wang ◽  
Chih-Ting Lin ◽  
Chi-Hsien Huang ◽  
Chao-Sung Lai ◽  
Chin-Hsiang Liao

Author(s):  
Sharon Cui ◽  
Dongseog Eun ◽  
Bozidar Marinkovic ◽  
Cheng-Yi Peng ◽  
Xiao Pan ◽  
...  

2021 ◽  
Vol 21 (8) ◽  
pp. 4216-4222
Author(s):  
Songyi Yoo ◽  
In-Man Kang ◽  
Sung-Jae Cho ◽  
Wookyung Sun ◽  
Hyungsoon Shin

A capacitorless one-transistor dynamic random-access memory cell with a polysilicon body (poly-Si 1T-DRAM) has a cost-effective fabrication process and allows a three-dimensional stacked architecture that increases the integration density of memory cells. Also, since this device uses grain boundaries (GBs) as a storage region, it can be operated as a memory cell even in a thin body device. GBs are important to the memory characteristics of poly-Si 1T-DRAM because the amount of trapped charge in the GBs determines the memory’s data state. In this paper, we report on a statistical analysis of the memory characteristics of poly-Si 1T-DRAM cells according to the number and location of GBs using TCAD simulation. As the number of GBs increases, the sensing margin and retention time of memory cells deteriorate due to increasing trapped electron charge. Also, “0” state current increases and memory performance degrades in cells where all GBs are adjacent to the source or drain junction side in a strong electric field. These results mean that in poly-Si 1T-DRAM design, the number and location of GBs in a channel should be considered for optimal memory performance.


D flip-flop is viewed as the most basic memory cell in by far most of computerized circuits, which brings it broad usage, particularly under current conditions where high-thickness pipeline innovation is as often as possible utilized in advanced coordinated circuits and flip-flop modules are key segments. As a constant research center, various sorts of zero flip-flops have been concocted and explored, and the ongoing exploration pattern has gone to rapid low-control execution, which can be come down to low power-defer item. To actualize superior VLSI, picking the most proper D flip-flop has clearly become an incredibly huge part in the structure stream. The quick headway in semiconductor innovation made it practicable to coordinate entire electronic framework on a solitary chip. CMOS innovation is the most doable semiconductor innovation yet it neglects to proceed according to desires past and at 32nm innovation hub because of the short channel impacts. GNRFET is Graphene Nano Ribbon Field Effect Transistor, it is seen that GNRFET is a promising substitute for low force application for its better grasp over the channel. In this paper, an audit on Dynamic Flip Flop and GNRFET is introduced. The power is improved in the proposed circuit for the D flip flop TSPC.


2013 ◽  
Vol 14 (5) ◽  
pp. 1231-1236 ◽  
Author(s):  
Min-Hoi Kim ◽  
Gyu Jeong Lee ◽  
Chang-Min Keum ◽  
Sin-Doo Lee

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