scholarly journals A Gated Diode DRAM Cell for Improved Power and Speed

In this paper performance analysis of Gated diode based Dynamic Random Access Memory (GD-DRAM) cell is compare with capacitor based DRAM cell in terms of average power dissipation, propagation delay, read access time and write access time at 250nm technology. The GD-DRAM is also referred as capacitorless DRAM. This gated diode stored data in DRAM which is an alternative solution to capacitor. This gated diode DRAM shows cutback in leakage and access time as compared to capacitor based DRAM. A gated diode is formed by shorting two terminal of MOS transistor i.e. source and drain. When the voltage Vgs is higher than knee voltage Vth; then data get stored on it. Nowadays dynamic random access memory is highly attracting market as compared static RAM because of its high package density, low cost and small area. In this paper this gated diode also resolves the issue of fabrication of capacitor in conventional DRAM cell. The major problem associated with DRAM is power dissipation. The above cells were designed and simulated in Tanner EDA tool and their results were analyzed at 250µm technology. Here we investigated that gated diode based DRAM has superior performance in terms of read time, write time and average power dissipation.

2021 ◽  
Vol 16 (1) ◽  
pp. 114-118
Author(s):  
Wan-Jun Yin ◽  
Tao Wen ◽  
Wei Zhang

This paper presents the design analysis of Dynamic Random Access Memory (DRAM) with one transistor one diode (1T1D). The proposed structure consists of one transistor and one voltage controlled diode capacitor. The word and bit lines are connected with two voltage sources for the write operation. The source and drain of the NMOS is tied together to form the diode structure. The off-state leakage current is the main cause for the power dissipation of DRAM. Thus the improvement of power efficiency to the overall system is a critical task. The conventional DRAM cell contains one capacitor and one transistor. But the absence of capacitor in the proposed work is advantageous by means of compatibility, scalability, fabrication complexity, and cost. Tanner EDA working platform of 7 nm technology is used for the implementation of 1T1D DRAM cell in proposed work. This work achieve the power dissipation, read and write access time in the range of 2.647 mW, 0.04 μs and 0.021 μs respectively. Also, the parameter comparison is performed by changing the technologies from 10 nm to 20 nm for 1T1D DRAM cell design.


Author(s):  
Harekrishna Kumar ◽  
V. K. Tomar

In the proposed work, a differential write and single-ended read half-select free 12 transistors static random access memory cell is designed and simulated. The proposed cell has a considerable reduction in power dissipation with better stability and moderate performance. This cell operates in subthreshold region and has a higher value of read static noise margin as compared to conventional six transistors static random access memory cell. A power cut-off technique is utilized between access and pull-up transistors during the write operation. It results in an increase in write static noise margin as compared to all considered cells. In the proposed cell, read and write access time is improved along with a reduction in read/write power dissipation as compared to conventional six transistors static random access memory cell. The bitline leakage current in the proposed cell is reduced which improves the [Formula: see text] ratio of the cell under subthreshold region. The proposed cell occupies less area as compared to considered radiation-hardened design 12 transistors static random access memory cell. The computed electrical quality metric of proposed cell is better among considered static random access memory cells. Process variation analysis of read stability, access time, power dissipation, read current and leakage current has been performed with the help of Monte Carlo simulation at 3,000 points to get more soundness in the results. All characteristics of static random access memory cells are compared at various supply voltages.


2021 ◽  
Vol 21 (8) ◽  
pp. 4258-4267
Author(s):  
Hee Dae An ◽  
Min Su Cho ◽  
Hye Jin Mun ◽  
Sang Ho Lee ◽  
Jin Park ◽  
...  

In this paper, we present a capacitorless one transistor dynamic random access memory (1T-DRAM) based on a polycrystalline silicon (poly-Si) double gate MOSFET with grain boundaries (GBs). Several studies have been conducted to implement 1T-DRAM using poly-Si. This is because poly-Si has the advantage of low-cost fabrication and can be stacked. However, poly-Si has GBs, which can adversely affect semiconductor device. So far, related studies on poly-Si-based 1T-DRAM have only focused on GBs present in the channel domain. Hence, in this study, we analyzed the transfer and memory characteristics when a GB is present in the source and drain regions. As a result, we found that in the center of the depletion region in the source and channel junction, where the effect of GB was most significant, sensing margins decreased the most from 0.88 to 0.29 μA/μm, and retention time (RT) decreased from 85 ms to 47 μs. In addition, we found that at the center of the depletion region in the drain and channel junction, where the effect of GBs was most significant in the drain region, RT decreased the most from 85 ms to 52 μs.


Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1454
Author(s):  
Yoshihiro Sugiura ◽  
Toru Tanzawa

This paper describes how one can reduce the memory access time with pre-emphasis (PE) pulses even in non-volatile random-access memory. Optimum PE pulse widths and resultant minimum word-line (WL) delay times are investigated as a function of column address. The impact of the process variation in the time constant of WL, the cell current, and the resistance of deciding path on optimum PE pulses are discussed. Optimum PE pulse widths and resultant minimum WL delay times are modeled with fitting curves as a function of column address of the accessed memory cell, which provides designers with the ability to set the optimum timing for WL and BL (bit-line) operations, reducing average memory access time.


Author(s):  
Zongliang Huo ◽  
Seungjae Baik ◽  
Shieun Kim ◽  
In-seok Yeo ◽  
U-in Chung ◽  
...  

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.


Author(s):  
Jitendra Kumar Mishra ◽  
Lakshmi Likhitha Mankali ◽  
Kavindra Kandpal ◽  
Prasanna Kumar Misra ◽  
Manish Goswami

The present day electronic gadgets have semiconductor memory devices to store data. The static random access memory (SRAM) is a volatile memory, often preferred over dynamic random access memory (DRAM) due to higher speed and lower power dissipation. However, at scaling down of technology node, the leakage current in SRAM often increases and degrades its performance. To address this, the voltage scaling is preferred which subsequently affects the stability and delay of SRAM. This paper therefore presents a negative bit-line (NBL) write assist circuit which is used for enhancing the write ability while a separate (isolated) read buffer circuit is used for improving the read stability. In addition to this, the proposed design uses a tail (stack) transistor to decrease the overall static power dissipation and also to maintain the hold stability. The comparison of the proposed design has been done with state-of-the-art work in terms of write static noise margin (WSNM), write delay, read static noise margin (RSNM) and other parameters. It has been observed that there is an improvement of 48%, 11%, 19% and 32.4% in WSNM while reduction of 33%, 39%, 48% and 22% in write delay as compared to the conventional 6T SRAM cell, NBL, [Formula: see text] collapse and 9T UV SRAM, respectively.


Sign in / Sign up

Export Citation Format

Share Document