Performance Degradation Due to Nonlocal Heating Effects in Resistive ReRAM Memory Arrays

MRS Advances ◽  
2019 ◽  
Vol 4 (48) ◽  
pp. 2593-2600 ◽  
Author(s):  
M. Al-Mamun ◽  
M. Orlowski
Keyword(s):  
Heat Dissipation ◽  
Heat Exposure ◽  
Memory Cell ◽  
Performance Degradation ◽  
Conduction Path ◽  
Pt Electrode ◽  
Heating Effects ◽  
Frequent Switching ◽  
Intermediate Cells ◽  
Nonlocal Heating

ABSTRACTFrequent switching of resistive memory cell may lead to a local accumulation of Joules heat in the device. Since the ReRAM cells are arranged in crossbar arrays with the two electrodes running perpendicular to each other, the heat generated in one device spreads via common electrode metal lines to the neighboring cells causing their performance degradation. Also cells that do not share any of the two electrodes (e.g. the diagonal array cells) with the hot device may also degrade provided the intermediate cells are set to an on-state establishing thus a continuous thermal conduction path between the heated and the probed device. It is found that the heat conduction along the active Cu electrode is more pronounced than that along the inert Pt electrode. Devices with Rh inert electrode performed better than those with Pt electrode due to better heat conductivity properties of Rh vs Pt. The heat dissipation is also found worse for a heated device with narrow and thin lines causing, however less degradation of more distant neighbor cells than for wide and thick metal lines. Finally, there is a trade-off between dissipating the heat quickly form the heated device to increase its maximum switching cycles and the heat exposure of the neighboring devices.

scholarly journals Performance Degradation of Nanofilament Switching Due to Joule Heat Dissipation

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 127
Author(s):  
Mohammad Shah Al-Mamun ◽  
Marius K. Orlowski
Keyword(s):  
Cross Talk ◽  
Heat Dissipation ◽  
Memory Cell ◽  
Performance Degradation ◽  
Joule Heat ◽  
Electrical Performance ◽  
Temperature Sensitive ◽  
Thermal Reliability ◽  
Crossbar Array ◽  
The Impact

When a memory cell of a Resistive Random Access Memory (ReRAM) crossbar array is switched repeatedly, a considerable amount of Joule heat is dissipated in the cell, and the heat may spread to neighboring cells that share one of the electrode lines with the heat source device. The remote heating of a probed memory cell by another cell allows separating the influence of temperature effects from the impact of the electric field on the resistive switching kinetics. We find that the cell-to-cell heat transfer causes severe degradation of electrical performance of the unheated neighboring cells. A metric for the thermal degradation of the I–V characteristics is established by a specific conditioning of a so-called “marginal” device used as a temperature-sensitive probe of electrical performance degradation. We find that even neighboring cells with no common metal electrode lines with the heated cell suffer substantial electrical performance degradation provided that intermediate cells of the array are set into a conductive state establishing a continuous thermal path via nanofilaments between the heated and probed cells. The cell-to-cell thermal cross-talk poses a serious electro-thermal reliability problem for the operation of a memory crossbar array requiring modified write/erase algorithms to program the cells (a thermal sneak path effect). The thermal cross-talk appears to be more severe in nanometer-sized memory arrays even if operated with ultra-fast, nanosecond-wide voltage/current pulses.

scholarly journals Thermal and Chemical Integrity of Ru Electrode in Cu/TaOx/Ru ReRAM Memory Cell

2019 ◽  
Vol 8 (12) ◽  
pp. N220-N233
Author(s):  
Mohammad Al-Mamun ◽  
Sean W. King ◽  
Marius Orlowski
Keyword(s):  
Memory Cell ◽  
Operating Conditions ◽  
Electrical Performance ◽  
Pt Electrode ◽  
Switching Performance ◽  
Inert Electrode ◽  
Work Function Difference ◽  
The Impact ◽  
Si Wafer

A good candidate for replacing the inert platinum (Pt) electrode in the well-behaved Cu/TaOx/Pt resistive RAM memory cell is ruthenium (Ru), already successfully deployed in the CMOS back end of line. We benchmark Cu/TaOx/Ru device against Cu/TaOx/Pt and investigate the impact of embedment of Cu/TaOx/Ru on two different substrates, Ti(20nm)/SiO2(730nm)/Si and Ti(20nm)/TaOx(30nm)/SiO2(730nm)/Si, on the cell's electrical performance. While the devices show similar switching performance at some operating conditions, there are notable differences at other operation regimes shedding light on the basic switching mechanisms and the role of the inert electrode. The critical switching voltages are significantly higher for Ru than for Pt devices and can be partly explained by the work function difference and different surface roughness of the inert electrode. The poorer switching properties of the Ru device are attributed to the degraded inertness properties of the Ru electrode as a stopping barrier for Cu+ ions as compared to the Pt electrode. However, some of the degraded electrical properties of the Ru devices can be mitigated by an improved integration of the device on the Si wafer. This improvement is attributed to the suppression of crystallization of Ru and its silicidation reactions that take place at elevated local temperatures, present mainly during the reset operation. This hypothesis has been corroborated by extensive XRD studies of multiple layer systems annealed at temperatures between 300K and 1173K.

scholarly journals The Physiology of Heat Tolerance in Small Endotherms

Physiology ◽  
2019 ◽  
Vol 34 (5) ◽  
pp. 302-313 ◽  
Author(s):  
Andrew E. McKechnie ◽  
Blair O. Wolf
Keyword(s):  
Climate Change ◽  
Body Temperature ◽  
Small Mammals ◽  
Heat Tolerance ◽  
Heat Dissipation ◽  
Heat Exposure ◽  
Tolerance Limits

Understanding the heat tolerances of small mammals and birds has taken on new urgency with the advent of climate change. Here, we review heat tolerance limits, pathways of evaporative heat dissipation that permit the defense of body temperature during heat exposure, and mechanisms operating at tissue, cellular, and molecular levels.

scholarly journals Mechanisms and modifiers of reflex induced cutaneous vasodilation and vasoconstriction in humans

2010 ◽  
Vol 109 (4) ◽  
pp. 1221-1228 ◽  
Author(s):  
Nisha Charkoudian
Keyword(s):  
Blood Flow ◽  
Human Skin ◽  
Skin Blood Flow ◽  
Cold Exposure ◽  
Heat Dissipation ◽  
Sympathetic Innervation ◽  
Heat Exposure ◽  
Reproductive Hormones ◽  
Excessive Heat ◽  
Cutaneous Vasodilation

Human skin blood flow responses to body heating and cooling are essential to the normal processes of physiological thermoregulation. Large increases in skin blood flow provide the necessary augmentation of convective heat loss during environmental heat exposure and/or exercise, just as reflex cutaneous vasoconstriction is key to preventing excessive heat dissipation during cold exposure. In humans, reflex sympathetic innervation of the cutaneous circulation has two branches: a sympathetic noradrenergic vasoconstrictor system, and a non-noradrenergic active vasodilator system. Noradrenergic vasoconstrictor nerves are tonically active in normothermic environments and increase their activity during cold exposure, releasing both norepinephrine and cotransmitters (including neuropeptide Y) to decrease skin blood flow. The active vasodilator system in human skin does not exhibit resting tone and is only activated during increases in body temperature, such as those brought about by heat exposure or exercise. Active cutaneous vasodilation occurs via cholinergic nerve cotransmission and has been shown to include potential roles for nitric oxide, vasoactive intestinal peptide, prostaglandins, and substance P (and/or neurokinin-1 receptors). It has proven both interesting and challenging that no one substance has been identified as the sole mediator of active cutaneous vasodilation. The processes of reflex cutaneous vasodilation and vasoconstriction are both modified by acute factors, such as exercise and hydration, and more long-term factors, such as aging, reproductive hormones, and disease. This review will highlight some of the recent findings in these areas, as well as interesting areas of ongoing and future work.

Self-Heating Effects in High-Power AlGaN/GaN HFETs

2001 ◽  
Vol 693 ◽  
Author(s):  
M. Kuball ◽  
M.J. Uren ◽  
J.M. Hayes ◽  
T. Martin ◽  
J.C.H. Birbeck ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Field Effect Transistors ◽  
Three Dimensional ◽  
Non Invasive ◽  
Self Heating ◽  
Heating Effects ◽  
Heterostructure Field Effect Transistors ◽  
Gan Heterostructure ◽  
Temperature Maps ◽  
Better Than

AbstractWe report on the non-invasive measurement of temperature, i.e., self-heating effects, in active AlGaN/GaN heterostructure field effect transistors (HFETs). Micro-Raman spectroscopy was used to produce temperature maps with ≈1 μm spatial resolution and a temperature accuracy of better than 10°C. Significant self-heating effects in the source-drain opening of AlGaN/GaN HFETs were measured. Devices grown on sapphire and SiC substrates were compared. Three-dimensional finite-difference heat dissipation calculations were performed as function of device geometry.

scholarly journals Thermoregulation in desert birds: scaling and phylogenetic variation in heat tolerance and evaporative cooling

2021 ◽  
Vol 224 (Suppl 1) ◽  
pp. jeb229211
Author(s):  
Andrew E. McKechnie ◽  
Alexander R. Gerson ◽  
Blair O. Wolf
Keyword(s):  
Heat Tolerance ◽  
Heat Dissipation ◽  
Arid Zone ◽  
Resting Metabolic Rate ◽  
Heat Exposure ◽  
Published Data ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Data Set ◽  
The Difference

ABSTRACTEvaporative heat dissipation is a key aspect of avian thermoregulation in hot environments. We quantified variation in avian thermoregulatory performance at high air temperatures (Ta) using published data on body temperature (Tb), evaporative water loss (EWL) and resting metabolic rate (RMR) measured under standardized conditions of very low humidity in 56 arid-zone species. Maximum Tb during acute heat exposure varied from 42.5±1.3°C in caprimulgids to 44.5±0.5°C in passerines. Among passerines, both maximum Tb and the difference between maximum and normothermic Tb decreased significantly with body mass (Mb). Scaling exponents for minimum thermoneutral EWL and maximum EWL were 0.825 and 0.801, respectively, even though evaporative scope (ratio of maximum to minimum EWL) varied widely among species. Upper critical limits of thermoneutrality (Tuc) varied by >20°C and maximum RMR during acute heat exposure scaled to Mb0.75 in both the overall data set and among passerines. The slope of RMR at Ta>Tuc increased significantly with Mb but was substantially higher among passerines, which rely on panting, compared with columbids, in which cutaneous evaporation predominates. Our analysis supports recent arguments that interspecific within-taxon variation in heat tolerance is functionally linked to evaporative scope and maximum ratios of evaporative heat loss (EHL) to metabolic heat production (MHP). We provide predictive equations for most variables related to avian heat tolerance. Metabolic costs of heat dissipation pathways, rather than capacity to increase EWL above baseline levels, appear to represent the major constraint on the upper limits of avian heat tolerance.

Thermal Analysis of a Face-to-Back Bonded Four-Layer Stacked 3D IC Model

2013 ◽  
Vol 562-565 ◽  
pp. 141-146
Author(s):  
Xiu Yun Du ◽  
Zhe Nan Tang
Keyword(s):  
Heat Dissipation ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Bottom Surface ◽  
Transient Temperature ◽  
Signal Delay ◽  
Conduction Path ◽  
3D Ic ◽  
Through Silicon Via ◽  
Interlayer Bonding

Three dimensional integrated circuits (3D ICs) consisted of stacking and vertically interconnecting are an emerging technology with great potential for improving system performance. 3D integration relies on Through Silicon Via (TSV) interconnection and interlayer bonding between the silicon layers. Due to the advantages of higher device density, lesser signal delay, shorter interconnection length and smaller package size, this technology attracts growing attentions. A number of innovative processes contribute to the realization of 3D IC. These include back grinding, coating, cleaning, etching, wafer thinning, filling of high aspect ratio vias with electroplated copper and interlayer bonding, etc. In this work, finite element models for four-layer stacked TSV-based (Through Silicon Via) 3D IC are established based on the heat distribution of working process caused by heat source in device die, in order to investigate the thermal effects and determine the improvements required. The transient temperature fields of 3D IC structures are obtained. The effects of various geometric parameters and thermal properties on the overall temperature have been analyzed. The result indicates that TSV diameter, pitch, BCB thickness and BEOL conductivity play more important roles to the temperature increment and the maximum temperature of no TSV structures is several times of that of TSV-based structures. The copper provides for an effective heat conduction path, and reduces considerably the overall temperature. It is also shown that the heat path from chip to the bottom surface is the main way for the heat dissipation.

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