Electrical Switching Characteristics of Nitrogen Doped Ge2Sb2Te5 Based Phase Change Random Access Memory Cell

2007 ◽  
Vol 124-126 ◽  
pp. 21-24 ◽  
Author(s):  
Myoung Sub Kim ◽  
Jin Hyung Jun ◽  
Jin Ho Oh ◽  
Hyeong Joon Kim ◽  
Jae Sung Roh ◽  
...  
Keyword(s):  
Phase Change ◽  
Nitrogen Doping ◽  
Bottom Electrode ◽  
Random Access ◽  
Memory Cell ◽  
Dynamic Resistance ◽  
Electrical Switching ◽  
Nitrogen Doped ◽  
Electrode Contact ◽  
Switching Characteristics

Ge2Sb2Te5 (GST) has been widely studied for PRAM as reversible phase change material. GST is expected to reduce RESET (crystalline → amorphous) operation power, which is one of important issues for PRAM technology. In order to investigate the effect of nitrogen doping on electrical switching characteristics, we fabricated two kinds of PRAM cells with nitrogen-doped (N-doped) and un-doped GST, which were different bottom electrode contact size (0.80~1.00 ). N-doped GST PRAM cells have higher dynamic resistance with small sized bottom electrode contact and lower RESET voltage (about 1.2 V, 50 ns) than un-doped GST PRAM cells (about 1.6 V, 50 ns). The resistance switching ratio (RRESET to RSET) was about 100. The results of this study indicate that nitrogen doping into GST film and smaller size of bottom electrode contact reduce RESET power for PRAM operation.

Effect of the Bottom Electrode Contact (BEC) on the phase transformation of N2 doped Ge2Sb2Te 5 (N-GST) in a Phase-change Random Access Memory

2004 ◽  
Vol 830 ◽  
Author(s):  
Suyoun Lee ◽  
Y. J. Song ◽  
Y. N. Hwang ◽  
S. H. Lee ◽  
J. H. Park ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Change ◽  
Bottom Electrode ◽  
Random Access ◽  
Surface Oxidation ◽  
Random Access Memory ◽  
Access Memory ◽  
Electrode Contact ◽  
Electrode Metal ◽  
Contact Size

With respect to the operation of a Phase-change Random Access Memory (PRAM or PcRAM), we studied the effect of the contact between the electrode metal and the chalcogenide glass, N2 doped Ge2Sb2Te5 in this report. We investigated a change of the resistance-programming current pulse (R-I) curve varying the contact size and the electrode material. Also we tested the surface oxidation of the electrode. We found that the programming current, the resistance of the programmed state (“RESET”) and the erased state (“SET”) were highly dependent on the above parameters. These results are presented and a more effective way to the high density PRAM will be proposed.

Performance improvement of phase-change memory cell with cup-shaped bottom electrode contact

2008 ◽  
Vol 93 (10) ◽  
pp. 103107 ◽  
Author(s):  
L. C. Wu ◽  
Z. T. Song ◽  
F. Rao ◽  
Y. F. Gong ◽  
B. Liu ◽  
...  
Keyword(s):  
Phase Change ◽  
Performance Improvement ◽  
Bottom Electrode ◽  
Phase Change Memory ◽  
Memory Cell ◽  
Electrode Contact ◽  
Change Memory

Temperature Dependence of Phase-Change Random Access Memory Cell

2006 ◽  
Vol 45 (5A) ◽  
pp. 3955-3958 ◽  
Author(s):  
X. S. Miao ◽  
L. P. Shi ◽  
H. K. Lee ◽  
J. M. Li ◽  
R. Zhao ◽  
...  
Keyword(s):  
Phase Change ◽  
Temperature Dependence ◽  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Access Memory

Simulation and Design of a Silicon Nanowire based Phase Change Memory Cell

2012 ◽  
Vol 1431 ◽  
Author(s):  
Ramin Banan Sadeghian ◽  
Yusuf Leblebici ◽  
Ali Shakouri
Keyword(s):  
Phase Change ◽  
High Speed ◽  
Low Cost ◽  
Silicon Nanowire ◽  
Phase Change Memory ◽  
Random Access ◽  
Memory Cell ◽  
Oxide Thickness ◽  
Nanowire Diameter ◽  
Change Memory

ABSTRACTIn this work we present preliminary calculations and simulations to demonstrate feasibility of programming a nanoscale Phase Change Random Access Memory (PCRAM) cell by means of a silicon nanowire ballistic transistor (SNWBT). Memory cells based on ballistic transistors bear the advantage of having a small size and high-speed operation with low power requirements. A one-dimensional MOSFET model (FETToy) was used to estimate the output current of the nanowire as a function of its diameter. The gate oxide thickness was 1.5 nm, and the Fermi level at source was set to -0.32 eV. For the case of VDS = VGS = 1 V, when the nanowire diameter was increased from 1 to 60 nm, the output power density dropped from 109 to 106 W cm-2 , while the current increased from 20 to 90 μA. Finite element electro-thermal analysis were carried out on a segmented cylindrical phase-change memory cell made of Ge2Sb2Te5 (GST) chalcogenide, connected in series to the SNWBT. The diameter of the combined device, d, and the aspect ratio of the GST region were selected so as to achieve optimum heating of the GST. With the assumption that the bulk thermal conductivity of GST does not change significantly at the nanoscale, it was shown that for d = 24 nm, a ‘reset’ programming current of ID = 80 μA can heat the GST up to its melting point. The results presented herein can help in the design of low cost, high speed, and radiation tolerant nanoscale PCRAM devices.

Design of Side Bottom-Electrode-Contact for High Density Phase-Change Memory Array

2012 ◽  
Vol 12 (10) ◽  
pp. 7939-7943
Author(s):  
Yan Liu ◽  
Zhitang Song ◽  
Bo Liu ◽  
Jia Xu ◽  
Houpeng Chen ◽  
...  
Keyword(s):  
Phase Change ◽  
Bottom Electrode ◽  
Phase Change Memory ◽  
High Density ◽  
Memory Array ◽  
Electrode Contact ◽  
Change Memory

Simulation Study on Heat Conduction of a Nanoscale Phase-Change Random Access Memory Cell

2006 ◽  
Vol 6 (11) ◽  
pp. 3474-3478
Author(s):  
JunHo Kim ◽  
Ki-Bong Song
Keyword(s):  
Phase Change ◽  
Electric Conductivity ◽  
Fem Simulation ◽  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Heat Transfer Characteristics ◽  
Temperature Dependent ◽  
Access Memory ◽  
Physical Quantities

We have investigated heat transfer characteristics of a nano-scale phase-change random access memory (PRAM) cell using finite element method (FEM) simulation. Our PRAM cell is based on ternary chalcogenide alloy, Ge2Sb2Te5 (GST), which is used as a recording layer. For contact area of 100 × 100 nm2, simulations of crystallization and amorphization processes were carried out. Physical quantities such as electric conductivity, thermal conductivity, and specific heat were treated as temperature-dependent parameters. Through many simulations, it is concluded that one can reduce set current by decreasing both electric conductivities of amorphous GST and crystalline GST, and in addition to these conditions by decreasing electric conductivity of molten GST one can also reduce reset current significantly.

3-D Finite Element Simulation of a Phase-change Random Access Memory Cell with a Self-insulated Structure

2008 ◽  
Vol 1108 ◽  
Author(s):  
Ke Sun ◽  
Wen Feng ◽  
Jae Young Lee ◽  
Biyun Li ◽  
Ya-Hong Xie
Keyword(s):  
Finite Element ◽  
Phase Change ◽  
Finite Element Simulation ◽  
Thermal Efficiency ◽  
Proximity Effect ◽  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Access Memory ◽  
Element Simulation

AbstractIn this paper, we proposed a phase-change random access memory (PCRAM) cell with a self-insulated structure (SIS), which is expected to have better thermal efficiency than the conventional structures. 3-D finite element simulation is used to study the most power consuming RESET process for both SIS and conventional normal bottom contact (NBC) cells driven by a MOSFET. Instead of programming current, power consumption is investigated to give a more fundamental comparison between the two structures. Thermal proximity effect for both kinds of cells is directly analyzed by simulating a 3×3 device array. The potential slow-quenching issue of SIS is also discussed.

Thermal analysis of nonvolatile and non rotation phase change memory cell

2003 ◽  
Vol 803 ◽  
Author(s):  
L. P. Shi ◽  
T. C. Chong ◽  
J. M. Li ◽  
H. X. Yang ◽  
J. Q. Mou
Keyword(s):  
Phase Change ◽  
Electric Pulse ◽  
Phase Change Memory ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Random Access ◽  
Current Density Distribution ◽  
Memory Cell ◽  
Temperature History ◽  
Change Memory

ABSTRACTIn this paper, a three-dimensional finite-element modeling is performed for the analyses of Chalcogenide Random Access Memory (C-RAM), a non-rotation nonvolatile phase change memory cell. The thermal effect generated by an incident electric pulse was mainly discussed. Thermal performances of the cell as a result of electrical and geometrical variations were quantified. Current density distribution, temperature profiles, temperature history, heating rate, cooling rate, and heat flow characteristics were obtained and analyzed. The study is useful for the failure analysis of the C-RAM.

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