First-Principles Modeling for Current-Voltage Characteristics of Resistive Random Access Memories

2013 ◽  
Vol 1562 ◽  
Author(s):  
Takehide Miyazaki ◽  
Hisao Nakamura ◽  
Kengo Nishio ◽  
Hisashi Shima ◽  
Hiroyuki Akinaga ◽  
...  
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
Electrode Materials ◽  
Random Access ◽  
Model Systems ◽  
Electronic Coupling ◽  
Current Ratio ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Non Equilibrium Green’S Function

ABSTRACTWe present results of first-principles non-equilibrium Green’s function calculations for current-voltage (IV) characteristics of the electrode/HfO2/electrode model systems. In order to investigate the effect of the electrode materials on the IV characteristics, we considered two transition metals for electrode, Ta and W, which are both body-centered-cubic elemental metals but have different valence numbers. We simulated the ON state by placing oxygen vacancies in the HfO2 layer while the OFF state was modeled with HfO2 without oxygen vacancies. At the OFF state, no electric current flowed for -1 V up to +1 V, as expected. At the ON state, however, we found that the absolute current for the Ta electrode was twice as large as that for the W electrode. The analysis of the IV characteristics shows that the electronic coupling between Ta and HfO2 is substantially stronger than that between W and HfO2. Our study demonstrates the importance of the matching between electrode and insulator materials to achieve a high ON- to OFF-current ratio in ReRAMs at a low bias.

scholarly journals Improved Device Distribution in High-Performance SiNx Resistive Random Access Memory via Arsenic Ion Implantation

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1401
Author(s):  
Te Jui Yen ◽  
Albert Chin ◽  
Vladimir Gritsenko
Keyword(s):  
High Performance ◽  
Conduction Mechanism ◽  
Random Access ◽  
Random Access Memory ◽  
Resistive Random Access Memory ◽  
Switching Behavior ◽  
Access Memory ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Limited Conduction

Large device variation is a fundamental challenge for resistive random access memory (RRAM) array circuit. Improved device-to-device distributions of set and reset voltages in a SiNx RRAM device is realized via arsenic ion (As+) implantation. Besides, the As+-implanted SiNx RRAM device exhibits much tighter cycle-to-cycle distribution than the nonimplanted device. The As+-implanted SiNx device further exhibits excellent performance, which shows high stability and a large 1.73 × 103 resistance window at 85 °C retention for 104 s, and a large 103 resistance window after 105 cycles of the pulsed endurance test. The current–voltage characteristics of high- and low-resistance states were both analyzed as space-charge-limited conduction mechanism. From the simulated defect distribution in the SiNx layer, a microscopic model was established, and the formation and rupture of defect-conductive paths were proposed for the resistance switching behavior. Therefore, the reason for such high device performance can be attributed to the sufficient defects created by As+ implantation that leads to low forming and operation power.

scholarly journals SIMULATING CHARACTERISTICS OF CARBON NANOTUBE FIELD- EFFECT TRANSISTOR (CNTFET)

2010 ◽  
Vol 13 (2) ◽  
pp. 15-27
Author(s):  
Hien Sy Dinh ◽  
Tuan Tran Anh Thi ◽  
Luong Thi Nguyen
Keyword(s):  
Field Effect Transistor ◽  
Oxide Thickness ◽  
Capacitive Coupling ◽  
Graphic User Interface ◽  
Current Voltage ◽  
Gate Oxide Thickness ◽  
Calculation Results ◽  
Current Voltage Characteristics ◽  
Effect Transistor ◽  
Non Equilibrium Green’S Function

We provide a model of coaxial CNTFET, using single wall nanotube. These devices would exhibit wrap-around gates that maximize capacitive coupling between the gate electrode and the nanotube channel. The results of simulations of I-V characteristics for CNTFETs are presented. Here we use non-equilibrium Green’s function (NEGF) to perform simulation for CNTFET. This simulator also includes a graphic user interface (GUI) of Matlab that enables parameter entry, calculation control, display of calculation results. In this work, we review the capabilities of the simulator, summarize the theoretical approach and experimental results. Current-voltage characteristics are a function of the variables such as: diameter of CNT, the length of CNT, the gate oxide thickness, gate voltage of Vg, types of materials of Source-Drain, Gate, and temperature. The obtained I-V characteristics of the CNTFET are also presented by analytical equations.

Poly-NiO/Nb:SrTiO3 Based Resistive Switching Device for Nonvolatile Random Access Memory

2012 ◽  
Vol 605-607 ◽  
pp. 1944-1947
Author(s):  
Cheng Hu ◽  
Yong Dan Zhu
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Carrier Injection ◽  
Forming Process ◽  
Switching Characteristic ◽  
Bipolar Resistive Switching ◽  
Retention Characteristic ◽  
Injection Process ◽  
Current Voltage ◽  
Current Voltage Characteristics

The bipolar resistive switching characteristic of Ag/poly-NiO/Nb:SrTiO3/In device has been investigated in this letter. The current-voltage characteristics of the device shows reproducible and pronounced bipolar resistive switching after 2V forming process and the resistive switching ratio RHRS/RLRS can reach 104 at the read voltage -0.5V. Multilevel memories can be realized by changing the max reverse voltages and show well retention characteristic even after several sweeping cycles. The results have been discussed in terms of carrier injection process via defects at the interface of the poly-NiO and Nb:SrTiO3.

Current-Voltage Characteristic of C-RAM Nano-Cell-Element

2007 ◽  
Vol 121-123 ◽  
pp. 591-594
Author(s):  
Bo Liu ◽  
Zhi Tang Song ◽  
Song Lin Feng ◽  
Bomy Chen
Keyword(s):  
Focused Ion Beam ◽  
Bottom Electrode ◽  
Ion Beam ◽  
Random Access ◽  
Access Memory ◽  
Cell Element ◽  
Current Voltage ◽  
Beam Method ◽  
Current Voltage Characteristics ◽  
Contact Size

Nano-cell-elements of chalcogenide random access memory (C-RAM) based on Ge2Sb2Te5 films have been successively fabricated by using the focused ion beam method. The minimum contact size between the Ge2Sb2Te5 phase change film and bottom electrode film in the nano-cell-element is in diameter of 90nm. The current-voltage characteristics of the C-RAM cell element are studied using the home-made current-voltage tester in our laboratory. The minimum SET current of about 0.3mA is obtained.

Characterizations of Mesa Structural Near-Infrared n-Type Nanocrystalline-FeSi2/p-Type Si Heterojunction Photodiodes at Low Temperatures

2013 ◽  
Vol 747 ◽  
pp. 217-220 ◽  
Author(s):  
Nathaporn Promros ◽  
Ryūhei Iwasaki ◽  
Suguru Funasaki ◽  
Kyohei Yamashita ◽  
Tsuyoshi Yoshitake
Keyword(s):  
Dark Current ◽  
Low Temperatures ◽  
Near Infrared ◽  
Device Performance ◽  
Current Ratio ◽  
Capacitance Density ◽  
Remarkable Improvement ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
P Type

In order to reduce the parasitic capacitance, mesa structural n-type NC-FeSi2/p-type Si heterojunctions were fabricated by photolithography. Their current-voltage characteristics were measured in the dark and under illumination using a 1.31 μm laser in the temperature range of 60 300 K. Their junction capacitance density was evidently reduced as compared with that of the normal structural diodes. The dark current was markedly reduced with a decrease in the temperature. At 60 K, a rectifying current ratio in the dark became more than five orders of magnitude at ±1V. The ratio of the photocurrent to the dark current was dramatically enhanced to be approximately two orders of magnitude, and the detectivity was calculated to be 1.5 × 1011 cmHz1/2/W at-1V. The obtained results showed a remarkable improvement in the device performance as compared with those at 300 K.

scholarly journals SIMULATING CURRENT - VOLTAGE CHARACTERISTICS OF MOLECULAR TRANSISTOR FIELD EFFECT TRANSISTOR

2009 ◽  
Vol 12 (13) ◽  
pp. 5-12
Author(s):  
Hien Sy Dinh ◽  
Trung Hoang Huynh
Keyword(s):  
Field Effect ◽  
High Speed ◽  
Field Effect Transistor ◽  
Promising Alternative ◽  
Current Voltage ◽  
Significant Difference ◽  
Current Voltage Characteristics ◽  
Effect Transistor ◽  
Non Equilibrium Green’S Function ◽  
Material Temperature

Molecular Field Effect Transistor (MFET) is a promising alternative candidate of traditional MOSFET in future due to its small size, low power consumption and high speed. In this work, we introduce a model of three-terminal MFET. The structure of the MFET is in shape like traditional MOSFET, but its conductive channel is replaced by a benzene-1,4-dithiolate molecule. We use non-equilibrium Green's function method to compute transport function of charges and ultimately, the current-voltage (1-V) characteristics. The program is written by using graphic user guide (GUI) in Matlab. We have found significant difference of I-V characteristics between MOSFET and MFET. In addition, impacts of types of material, temperature, and bias on I-V characteristics of the MFET have been considered. Using GUI in Matlab, obtained results of simulations are intuitively displayed.

scholarly journals Simulation of current-voltage characteristics of graphene field effect transistor (GFET)

2013 ◽  
Vol 16 (3) ◽  
pp. 5-12
Author(s):  
Hien Sy Dinh
Keyword(s):  
Field Effect ◽  
Function Method ◽  
Field Effect Transistor ◽  
Graphic User Interface ◽  
Graphene Field Effect Transistor ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Effect Transistor ◽  
Graphene Fet ◽  
Non Equilibrium Green’S Function

Graphene has been one of the most vigorously studied research materials. We have developed a program for simulation of graphene field effect transistor (GFET). In this work, we use the simulation program to explore the performance of graphene FET. The simple model of the graphene FET is based on non-equilibrium Green’s function method and first is implemented by using graphic user interface of Matlab. The current-voltage characteristics of the GFET and affects of channel materials, gate materials, size of graphene FET, temperature on the characteristics are explored.

Negative differential resistance in “sulflower”-based molecular junction predicted by first-principles study

2021 ◽  
pp. 2150167
Author(s):  
Ji-Mei Shen ◽  
Jing Liu
Keyword(s):  
First Principles ◽  
Coulomb Blockade ◽  
Negative Differential Resistance ◽  
Local Density ◽  
Differential Resistance ◽  
Differential Conductance ◽  
First Principles Study ◽  
Current Voltage ◽  
Potential Applications ◽  
Current Voltage Characteristics

The electronic transport behavior of a sulflower molecule sandwiched between metal leads by S atom connecting apex Au or Ag atoms was investigated using a first-principles study by current-voltage characteristics, transmission spectrum and local density of states. Negative differential resistance (NDR) effect which originates from Coulomb blockade driven by bias was obtained. We also found that the differential conductance can be modulated by the metal leads with different work functions, which promise the potential applications in molecular devices in the future.

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