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We report a water-soluble and non-toxic method to incorporate additional extracellular matrix proteins into gelatin hydrogels, while obviating the use of chemical crosslinkers such as glutaraldehyde. Gelatin hydrogels were fabricated using a range of gelatin concentrations (4%-10%) that corresponded to elastic moduli of approximately 1 kPa-25 kPa, respectively, a substrate stiffness relevant for multiple cell types. Microbial transglutaminase was then used to enzymatically crosslink a layer of laminin on top of gelatin hydrogels, resulting in 2-component gelatin-laminin hydrogels. Human induced pluripotent stem cell derived spinal spheroids readily adhered and rapidly extended axons on GEL-LN hydrogels. Axons displayed a more mature morphology and superior electrophysiological properties on GEL-LN hydrogels compared to the controls. Schwann cells on GEL-LN hydrogels adhered and proliferated normally, displayed a healthy morphology, and maintained the expression of Schwann cell specific markers. Lastly, skeletal muscle cells on GEL-LN hydrogels achieved long-term culture for up to 28 days without delamination, while expressing higher levels of terminal genes including myosin heavy chain, MyoD, MuSK, and M-cadherin suggesting enhanced maturation potential and myotube formation compared to the controls. Future studies will employ the superior culture outcomes of this hybrid substrate for engineering functional neuromuscular junctions and related organ on a chip applications.

INTRODUCTION: Multicellular platforms and linked multi organ on chip devices are powerful tools for drug discovery, and basic mechanistic studies. Often, a critical constraint is defining a culture medium optimal for all cells present in the system. In this study, we focused on the key cells of the neuromuscular junction i.e., skeletal muscle and motor neurons. METHODS: Formulation of a chemically defined medium for the co-culture of C2C12 skeletal muscle cells and human induced pluripotent stem cell (hiPSC) derived spinal spheroids (SpS) was optimized. C2C12 cells in 10 experimental media conditions and 2 topographies were evaluated over a 14-day maturation period to determine the ideal medium formulation for skeletal muscle tissue development. RESULTS: During early maturation, overexpression of genes for myogenesis and myopathy was observed for several media conditions, corresponding to muscle delamination and death. Together, we identified 3 media formulations that allowed for more controlled differentiation, healthier muscle tissue, and long-term culture duration. This evidence was then used to select media formulations to culture SpS and subsequently assessed axonal growth. As axonal growth in SpS cultures was comparable in all selected media conditions, our data suggest that the neuronal basal medium with no added supplements is the ideal medium formulation for both cell types. CONCLUSIONS: Optimization using both topographical cues and culture media formulations provides a comprehensive analyses of culture conditions that are vital to future applications for in vitro NMJ models. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12195-020-00624-1) contains supplementary material, which is available to authorized users.

Through the use of stem cell-derived cardiac myocytes, tissue-engineered human myocardial constructs are poised for modeling normal and diseased physiology of the heart, as well as discovery of novel drugs and therapeutic targets in a human relevant manner. This review highlights the recent bioengineering efforts to recapitulate microenvironmental cues to further the maturation state of newly differentiated cardiac myocytes. These techniques include long-term culture, co-culture, exposure to mechanical stimuli, 3D culture, cell-matrix interactions, and electrical stimulation. Each of these methods has produced various degrees of maturation; however, a standardized measure for cardiomyocyte maturation is not yet widely accepted by the scientific community.

Objective Demyelination that results from disease or traumatic injury, such as spinal cord injury (SCI), can have a devastating effect on neural function and recovery. Many researchers are examining treatments to minimize demyelination by improving oligodendrocyte availability in vivo. Transplantation of stem and oligodendrocyte progenitor cells is a promising option, however, trials are plagued by undirected differentiation. Here we introduce a biomaterial that has been optimized to direct the differentiation of neural progenitor cells (NPCs) toward oligodendrocytes as a cell delivery vehicle after SCI. Approach A collagen-based hydrogel was modified to mimic the mechanical properties of the neonatal spinal cord, and components present in the developing extracellular matrix were included to provide appropriate chemical cues to the NPCs to direct their differentiation toward oligodendrocytes. The hydrogel with cells was then transplanted into a unilateral cervical contusion model of SCI to examine the functional recovery with this treatment. Six behavioral tests and histological assessment were performed to examine the in vivo response to this treatment. Main results Our results demonstrate that we can achieve a significant increase in oligodendrocyte differentiation of NPCs compared to standard culture conditions using a three-component biomaterial composed of collagen, hyaluronic acid, and laminin that has mechanical properties matched to those of neonatal neural tissue. Additionally, SCI rats with hydrogel transplants, with and without NPCs, showed functional recovery. Animals transplanted with hydrogels with NPCs showed significantly increased functional recovery over six weeks compared to the media control group. Significance The three-component hydrogel presented here has the potential to provide cues to direct differentiation in vivo to encourage regeneration of the central nervous system.

During NiPtSi contact electrode processing and after the first thermal treatment to form Ni rich silicide, excessive Ni is removed by a strong acid mixture such as piranha (mixture of sulfuric acid and hydrogen peroxide. The post salicidation clean process has to be selective to all exposed materials: Si3N4, SiO2, NiPtSi, and NiPtSiGe (contact electrodes of source/drain for strain applications)). Performing a partition process with RTA1 (rapid thermal annealing) followed by Ni strip, followed by RTA2, and then with Pt strip is one method to check for NiPt removal. The Ni strip was performed using dilute nitric acid (20:1) and dilute aqua regia (1:5:4) and showed completed NiPt removal. A queue time study was also investigated after the Ni strip and after RTA2 for defect formation. Also, Pt removal using aqua regia solutions of various shelf-lives were tested. The result led to the conclusion that solutions of aqua regia with longer shelf-lives were also shown to be less effective in Pt residue removal. Using a High Productivity Combinatorial materials/process screening technique to reduce the number of product wafers used for evaluation process development, the etch rates of all the materials of interest were tested on blanket wafers. The chemistry consists of varying acid and base types and the relative combinations of these chemistries. Process conditions that consisted of various process chemistries, process temperatures, and degrees of fluid agitation (e.g. stirrer speed) were done on the same substrate.

In this paper we will report the results of TiN metal gate recession using a dilute mixture of sulfuric acid, hydrogen peroxide and hydrofluoric acid known by the trade name DSP+

A novel metallization scheme was developed to enable advanced BEOL interconnect scaling. The proposed approach adopts electroless Co to selectively grow Co in vias, followed by conventional Cu metallization for the trench. We have demonstrated the feasibility of this approach through the process integration of electroless Co via pre-fill on a two metal layer interconnect test structure. A detailed discussion on the yield improvement, parametric data, and reliability will be presented in this paper.

The manufacture of ultra-large scale integration technology requires many thermal cycles that can impose significant strain within the constituent metallization due to the mismatch in coefficients of thermal expansion between metallization and its surrounding environment. The resulting stress distributions can be large enough to induce voiding within Cu-based metallization, a key reliability issue that must be addressed. In particular, the interface between the Cu and overlying capping layers is a critical location associated with void formation. By combining conventional and glancing-incidence X-ray diffraction measurements, we can investigate depth-dependent stress distributions that develop in Cu films and patterned features. In-situ annealing and as-deposited measurements reveal that strain gradients are created in capped Cu structures, where an increased in-plane tensile stress is generated near the Cu / cap interface. The interplay between plasticity in the Cu and the constraint imposed by capping layers dictates the extent of the observed gradients. For example, Cu films possessing caps deposited in a temperature regime where the Cu experienced only elastic deformation did not exhibit depth-dependent stress distributions. However, all capped Cu samples exposed to temperatures high enough to induce plastic behavior developed greater tensile stress at the Cu / cap interface than in the bulk of the Cu film after cooling, representing a clear concern to the mitigation of metallization voiding.

The presence of voids in Cu metallization represents a key reliability issue for ultra-large scale integration technology. In particular, the interface between the Cu and capping layers represents a critical location where the stress state of the Cu must be experimentally determined. Glancing-incidence X-ray diffraction (GIXRD) can be used to investigate depth-dependent stress distributions within electroplated Cu films induced by overlying capping layers. A combination of conventional X-ray diffraction measurements and GIXRD results revealed that strain gradients were created in Cu films and patterned features possessing a SiC"xN"yH"z cap, where an increased in-plane tensile stress was generated near the film/cap interface due to the constraint imposed by the SiC"xN"yH"z layer during cooling from the cap deposition temperature. Cu films possessing a CoWP cap, deposited at lower temperatures where the Cu experienced only elastic deformation, did not exhibit depth-dependent stress distributions. However, all Cu samples exposed to the SiC"xN"yH"z deposition temperature developed stress gradients regardless of the capping material. Although in situ annealing of SiC"xN"yH"z capped Cu films decreased the stress gradient as the sample temperature approached that of the cap deposition, the gradient reappeared upon cooling to room temperature.

Environmentally assisted debonding at Cu/barrier interfaces is reported for oxidizing and reducing environments. Both moist and dry oxidizing environments are considered, and the effects of different oxidizing species and their chemical activity on the rate of debonding of a Cu/SiN interface is quantified. The type of oxidizing species is shown to play a critical role in the kinetics of environmentally assisted debonding. Additionally, the effect of varying the activity and temperature of reducing hydrogen environments is investigated. The mechanisms responsible for environmentally assisted debonding of Cu/SiN and Cu/SiCN interfaces are elucidated using an atomistic bond rupture model. An activation energy for debonding of Cu/SiCN interfaces in a hydrogen environment is calculated. Finally, a connection between environmentally assisted debonding and the time-dependent dielectric breakdown properties of Cu interconnects is proposed.

BACKGROUND: Periodic lateralised epileptic discharges (PLEDs) are associated with seizures and other clinical abnormalities and represent a transient EEG phenomenon. A substantial debate still remains as to whether they represent an ictal pattern as part of a status epilepticus. METHOD: A case report is presented with a clinical-electroencephalographic correlation RESULTS: An 18-year-old woman experienced a single unprovoked secondary generalised epileptic seizure with a transient cognitive decline. She recovered completely within weeks, while demonstrating frontal PLEDs in serial EEG recordings over 2 years and 3 months. Brain MRI and SPECT showed no abnormalities. CONCLUSION: In this case PLEDs were persistent and represented an isolated EEG finding. This argues against the hypothesis of an ictal pattern.

BACKGROUND: Oxaliplatin is a new generation platinum derivative, and has become a part of the medical treatment for solid cancer. It induces two distinct forms of neurotoxicity. An acute reversible syndrome shortly after the infusion is attributed to the transient hyperexcitability of the peripheral nerves and a dose-limiting chronic sensory neuropathy results from the cumulative toxic doses. This study was undertaken to evaluate the incidence and pattern of the clinical and electrophysiological abnormalities with the transient hyperexcitability syndrome. METHODS: 22 patients received Oxaliplatin as part of the FOLFOX schedule for anticancer therapy. Clinical symptoms were assessed by a standardized questionnaire. Electrophysiological investigations included sensory and motor nerve conduction studies of the median nerve and an electromyogram of the thenar. Investigations were performed 24 hours following Oxaliplatin and 13 days thereafter. RESULTS: 72% of the patients reported symptoms after Oxaliplatin, predominantly cold-induced painful parethesias of the hands, legs and throat and muscle cramps in the respective regions. They were more frequent in the second or further FOLFOX cycles and more disabling with higher cumulative doses. Myokymia and muscle twitching was seen in 47%. Thirteen days thereafter the above-mentioned symptoms had resolved completely. Nerve conduction studies did not differ at both times. After Oxaliplatin, single motor nerve stimuli induced repetitive muscle action potentials in 70% of the patients and the EMG disclosed neuromyotonic discharges in 85%. The more severe the clinical complaints, the more prominent were the electrophysiological abnormalities. However, even in 5 out of 6 asymptomatic patients electrophysiological abnormalities were evident. 13 days thereafter, except one patient, all abnormalities had subsided. CONCLUSION: This study confirms the high incidence of acute but reversible adverse events with Oxaliplatin therapy and highlights the nerve conduction studies and the EMG as valuable tools to disclose this hyperexcitablity syndrome of the peripheral nerve.

In the integrated circuit industry, aluminum-based interconnects and oxide interlayer dielectrics have been replaced with copper interconnects in a dual inlaid architecture and with low-K dielectrics. Inlaid Cu lines offer higher conductivity, improved electromigration performance and a reduced cost of manufacturing. In this manuscript, the current challenges with integrating Cu in high-performance integrated circuits are detailed. As technologies scale, the many steps in the integrated process flow cannot be viewed as independent. The interactions between process steps (module interactions) that must be considered will be discussed. The development of a reliable and manufacturable technology requires a fundamental understanding of these interactions. A process-oriented finite element model (FEM) will be presented to capture the effect of individual process steps on the stress evolution during processing. Finally, the future trends for Cu interconnect will be suggested.

Neurologische paraneoplastische Syndrome sind seltene, meist immunvermittelte Begleiterscheinungen von bosartigen Tumoren. Unter den zahlreichen Tumoren sind das Ovarial- und das Mammakarzinom eine haufige Ursache und damit eine Herausforderung an den Gynakologen. Das typische Erscheinungsbild besteht in der raschen Entwicklung einer schweren neurologischen Behinderung bei einem bisher nicht bekannten und lokal begrenzten Tumor. Neben der paraneoplastischen zerebellaren Degeneration mit einer schweren Ataxie als haufigstem Erscheinungsbild sind die limbische Enzephalitis, die Hirnstammenzephalitis, die sensorische Neuronopathie, das Stiff-Person-Syndrom, die Dermatomyositis und die paraneoplastische Retinopathie beschrieben. Der Meilenstein fur die Diagnose sind onkoneurale Antikorper im Serum und Liquor, die sowohl an Tumorzellen als auch an Nervenzellen binden. Neurologische paraneoplastische Syndrome bei Frauen mit Ovarial- und Mammakarzinomen haben immer eine ungunstige Prognose. Die meisten Patienten bleiben trotz einer effektiven Antitumortherapie, die Voraussetzung fur eine wirksame Immuntherapie ist, schwer behindert und die Mortalitat ist hoch. Paraneoplastic neurologic disorders are rare manifestations of a malignant neoplasm and mostly immune-mediated. Out of a broad spectrum of tumors ovarian and breast carcinomas are frequently the underlying cause presenting a challenge for the gynecologist. The combination of a rapidly progressive severe neurologic disability and a small, as yet unknown tumor is the typical clinical presentation. In addition to the most frequent paraneoplastic cerebellar degeneration resulting in severe ataxia, limbic encephalitis, brain stem encephalitis, sensory neuropathy, stiff-person syndrome, dermatomyositis and paraneoplastic retinopathy have been described. The cornerstone for the diagnosis are onconeural antibodies in serum and cerebrospinal fluid reacting with both the nervous system and the underlying cancer. Paraneoplastic neurologic syndromes in women with ovarian or breast cancer imply a grave prognosis. Although antitumor therapy may be effective in many cases and are essential for the success of additional immunotherapy, most patients remain severely disabled and mortality is remarkably high.

For optimum fabrication and usage of Cu films, an understanding of the relationship between processing and microstructure is required. The existence of twins is another significant factor for texture development in Cu films. Texture character and strength in the Cu film is dependent on the twin boundary development that is a function of processing conditions and film thickness. In this study, determination of grain growth and texture in the sputtered and electroplated Cu films during annealing was performed for films of 100, 480 and 850 nm in thickness deposited on a Ta(25 nm)/Si wafer. The texture was measured by X-ray pole figure. The effect of film thickness on the annealing texture in the sputtered and electroplated Cu films is examined and discussed.

Nickel and cobalt silicides have formation and/or stability issues when forming in the presence of Ge. Additions of Ge increase the temperature at which a low resistance CoSi"2 is formed due to phase separation into CoSi"2 and Ge-rich Si-Ge grains. With Ni, additions of Ge decrease the temperature at which NiSi converts to a NiSi"2, lead to agglomeration at a lower temperature and lead to germanosilicide formation. Nickel has a ''must not exceed'' critical temperature that decreases with increasing Ge concentration, and Co has a minimum critical temperature that increases with increasing germanium concentration. Neither silicide is ideal for doped Si-Ge contacts, where the germanium compositions are in excess of 20%. The insertion of a layer of pure Si above the Si-Ge is a promising integration option for forming a robust silicide on Si-Ge substrates. The phase formation and stability of pure Co on Si-20%Ge substrates with Si caps of thickness from 200 to 1000A were studied and it was shown that a 400A Si cap on Si-20%Ge leads to low resistance CoSi"2.

This letter reports the first replacement (Damascene) metal gate pMOSFETs fabricated with Ni/TaN, Co/TaN stacked electrode, where Ni or Co is in direct contact with the gate SiO/sub 2/, to adjust the electrode metal work function and TaN is used as the filling material for the gate electrode to avoid wet etching and CMP problems. The process is similar to the fabrication of traditional self-aligned polysilicon gate MOSFETs, except that in the back end (after the source/drain implants are activated) a few processing steps are added to replace the polysilicon with metal. Our data show that the Ni or Co/TaN gate electrode has the right work function for the pMOSFETs. The metal gate process can reduce the gate resistivity. Thermal stability of the stacked electrodes is studied and the result is reported in this paper. The damascene process flow bypasses high temperature steps (> 400/spl deg/C)critical for metal gate and hi k materials. This paper demonstrates that a low temperature anneal (300/spl deg/C) can improve the device performance. In this paper, the gate dielectrics is SiO/sub 2/.

The stiff-person syndrome is a rare but characteristic paraneoplastic condition in patients with breast cancer. We describe a 44-year-old woman with typical neurological deficits. Symptomatic treatment, before breast cancer was diagnosed, was ineffective. The neurologic symptoms improved dramatically after breast cancer was diagnosed and treated with surgery and adjuvant cyclophosphamide, methotrexate and 5-fluorouracil. Cyclophosphamide-based chemotherapy appears an effective way to treat the autoimmune etiology of the paraneoplastic syndrome.

Metal-Insulator-Semiconductor (MIS) Schottky diodes were fabricated to study Fermi level unpinning by use of a thin TiO x insulator. For Ti-TiO x -n-Si junctions, the Schottky barrier height (SBH) was pinned due to O diffusion from TiO x into Ti during thermal anneals, as observed from XPS depth profiles. A thin AlO x barrier inserted between the Ti and the TiO x prevented O diffusion from TiO x into Ti, allowing SBH unpinning to be maintained after 450 °C anneals.

The atomic transport processes which could cause degradation mechanisms in Cu interconnects are described. The influence of interconnect line width, barrier type and anneal process on the microstructure and reliability of the inlaid Cu lines are discussed. Grain size and texture measurements have been performed at blanket films and at arrays of Cu lines using advanced analytical techniques. The median grain size decreases with decreasing line width, and it can be influenced by heat treatments. The crystallographic texture is predominantly {111} out-of-plane with sidewall-oriented grains in narrow Cu lines. The grains have an in-plane preferred orientation with the 〈110〉 direction parallel to the sidewall normal. The Cu texture is influenced by barrier structure and thickness.

The microstructure of inlaid Cu lines has been quantified as a function of annealing conditions, post-plating, and post-CMP. The grain size distribution was measured using the median intercept method, crystallographic texture was characterized by pole figure analysis, and mechanical stress was determined using x-ray diffraction. The median grain size and mechanical stress level increase with increasing anneal temperature. The crystallographic texture is independent of the anneal temperature and is predominantly (111) with a small fraction of sidewall-nucleated (111) grains. The (111) grains nucleated from the trench bottom have a preferred in-plane orientation. The grain growth in the trench is independent of that in the overburden.

Far-field somatosensory evoked potentials (SSEPs) after median nerve stimulation were recorded from scalp- (Fz), epidural- (ED) and intravascular electrodes (basilar artery [Bas]) to study the nature of the controversial N18a component of the widespread N18 potential. In healthy volunteers frequently an N18a potential was recorded at Fz. Simultaneous Fz and ED recordings at the pontomesencephalic junction as well as Bas-recordings at the caudal basilar artery showed N18a components identical in latency and shape. With intravascular recordings the shapes differed between the top of the basilar artery and the caudal artery recordings. These findings support the existence of a separate N18a potential. The generator of the N18a is likely to be localized within the upper brainstem.

In this work, the phase formation is compared for Ni- and Co-silicidation with and without Ti cap. In addition, the electrical performance of Ni-silicidation with and without Ti-cap is investigated and compared to the performance of a Co-silicidation process with a Ti cap that has the same Si consumption. The lateral confinement of the silicide in the active areas is also studied.

CoSi/sub 2/ is being used commonly for the advanced IC technologies. There are several process choices to be made for the formation of a high yielding and reproducible silicide. In this paper the various CoSi/sub 2/ technologies are discussed. The scalability of the process of record, the Co/Ti(cap) process are presented for 0.18 /spl mu/m and below.

The texture of electroplated Cu lines of 0.375, 0.5 and 1.5 μm widths with Ta and TiN barrier layers was analyzed using x-ray pole figure and electron backscatter diffraction (EBSD) techniques. Both techniques indicate a strong (111) fiber texture relative to the bottom surface of the trench for samples with a Ta barrier layer and a 400 °C, 30 min, postelectroplating anneal. Samples with a TiN barrier and no anneal exhibit a weak (111) texture. For both barrier layers the quality of the texture, as measured by (111) peak intensity, fraction of randomly oriented grains and (111) peak width, degrades with decreasing linewidth. EBSD data also indicate (111) texture relative to the sidewalls of the trench in samples with a Ta barrier and postelectroplating anneal. Electromigration tests at 300 °C of 0.36 μm damascene Cu lines with the same process conditions show that samples with very weak (111) texture have median time to failures that exceed those of the strongly textured Cu lines. These results indicate t...

PURPOSE Levetiracetam (LEV) is a new antiepileptic drug which is increasingly being used intravenously as acute therapy for epileptic seizures and status epilepticus. Due to its minimal adverse events and the lack of a hepatic metabolism it is a suitable alternative in the emergency treatment of elderly patients. This study examines the tolerability and pharmacokinetics of fast intravenous infusions of LEV with elderly epileptic patients. PATIENTS AND METHODS Thirteen patients with a mean age of 72 years were treated with LEV IV for acute epileptic seizures or status epilepticus. 2000 mg were given within a period of 15 or 5 minutes. The LEV level was determined within 30 to 60 minutes after administration as well as 6, 12 and 24 hours later. Level of consciousness, respiration and cardiovascular functions were monitored. RESULTS 30 to 60 minutes following administration the mean plasma level of LEV was 48 mg/L; after 6, 12 and 24 hours 31, 20 and 17 mg/L, respectively. Eight out of the thirteen patients showed a cessation of ictal activity among which five were definitely responders to LEV. Alterations in the level of consciousness, respiration and cardiovascular functions did not occur. CONCLUSION 2000 mg LEV IV can be given to elderly and multimorbid patients within a period of 5 - 15 minutes without experiencing major adverse events. With this infusion rate plasma concentrations are > 40 mg/L immediately after infusion and 24 hours later > 10 mg/L. For half of the patients with status epilepticus LEV was an effective antiepileptic drug.

An integrated aluminum metallization process (Cool Al technology) was successfully applied to fabricate device wafers for the 0.25-μm technology. This new technology integrates CVD and PVD aluminum thin film deposition processes into a high vacuum cluster tool, the applied materials’ Endura, and is capable of reliable contact and via fills of high aspect ratio (>8:1) structures at low temperatures, typically around 330–400°C. Two different Cool Al integration sequences employing CVD TiN and Ti as liners were used to process device wafers with 0.3 and 0.4×1.2μm via structures. The fill performance and electrical and reliability characteristics of the devices were evaluated. Void-free fills of all via structures were achieved. In comparison with a standard W-plug process, both Cool Al splits show more than five times reduction in via resistance. The two Cool Al sequences yielded excellent electromigration (EM) reliability, equivalent or better than a standard W-plug process. Interestingly, the two Cool Al splits, with very different aluminum crystal textures, resulted in similar EM performance.

Die Fruhverschlusrate von Bypasses liegt bei 20%, die postoperative Infarktrate bei 5–8%, trotz der ublichen Sofort-Rethoraktomie bei postoperativer transmuraler Ischamie. Hierbei ist haufig mit erheblicher Zeitverzogerung zu rechnen, da ein Operationssaal meist nicht frei ist.

The role of crystallographic texture in electromigration resistance of interconnect lines is well documented. The presence of a strong (111) fiber texture results in a more reliable interconnect structure. It is also generally accepted that grain-boundary diffusion is the primary mechanism by which electromigration failures occur. It has been difficult to this point, however, to obtain statistically reliable information of grain-boundary structure in these materials as transmission electron microscopy investigations are limited by tedious specimen preparation and small, nonrepresentative, imaging regions. The present work focuses upon characterization of texture and grain-boundary structure of interconnect lines using orientation imaging microscopy, and particularly, upon the linewidth dependence of these measures. Conventionally processed Al–1%Cu lines were investigated to determine the affects of a postpatterning anneal on boundary structure as a function of linewidth. It was observed that texture tende...

X-ray diffraction has been used to measure the strain relaxation in passivated Al–0.5% Cu lines at 200 °C after cooling directly from an anneal at the passivation deposition temperature of 380 °C. Fits to the measured X, Y, and Z components of strain are summed to obtain the hydrostatic component, which exhibits a decay over time. Three mechanisms are considered to explain the decay of the hydrostatic strain in the metal line: Cu precipitation from the solid solution, the presence and growth of voids in the lines, and time-dependent deformation of the passivation. Calculations of the effect of Cu precipitation from the solid solution demonstrate that it plays an insignificant role in the relaxation. A high-voltage scanning electron microscope is used to image the presence and growth of voids through the passivation. The time scale of the growth of stress-induced voids is not the same as the hydrostatic relaxation, indicating that voiding is not solely responsible for the observed relaxation. The relaxation of the line is modeled using a time-dependent finite element model, allowing elastic compliance of the passivation. The magnitude of the calculated relaxation agrees with the measurements. It is suggested that a combination of voiding and passivation compliance is responsible for the measured hydrostatic strain relaxation in the metal line.

In this study, electromigration (EM) of interconnects (90 nm pitch) with airgaps was investigated using a combination of computational mechanics, analytical modelling, and EM experiments. EM experiments reveal that airgapped Cu lines without dielectric liner (non-capsulated) fail early by voiding in the EM tests due to oxidation and deterioration of interfacial adhesion at Cu interfaces. Also at high temperature regimes, extrusive failures under thermal compressive stresses were observed in airgapped Cu lines without dielectric liner. Therefore, Cu encapsulation using a conformal dielectric liner of adequate thickness is necessary in order to ensure hermeticity and provide endurance to the thermal and EM induced extrusive stresses. For an airgapped interconnect with a hermetic 5 nm PECVD conformal carbon doped silicon nitride (SiCN) liner deposited at 370 °C, a (jL)crit comparable to that of non-airgapped interconnects (with ultra-low-k dielectric 2.5 inter-layer dielectric) was predicted by the simulatio...

Due to the offset in the valence band, strained-Si nMOSFETs exhibit a -100 mV threshold shift and 4% degradation of the subthreshold slope per each 10% increase of Ge content in the relaxed SiGe layer. The correlation between the threshold shift and strained layer thickness is investigated based on device simulations. In a certain range of the strained-Si layer thickness, the threshold and subthreshold slope change gradually, posing a concern of larger device parameter variation. A larger threshold distribution is observed in devices fabricated with a strained layer thickness comparable to the depletion depth.

This work describes a low-temperature metal annealing technique that can be a helpful tool for fabricating the gate electrode of replacement metal gate CMOS transistors. The goal of the technique is to form doped metal (TaSiN, TiSiN, TaCN, TaPN, etc.) to change the work function of the metal gate electrode. The low-temperature doping process was performed in an ambient containing the precursors of the dopants, including silane, phosphine, and carbon-rich organic precursors. Experiments have been conducted to incorporate dopants such as P, C, Si into TaN or TiN. The transistor and C-V data show the resultant doped metals are suitable materials for P- and N-MOSFETs by providing the right metal work function.

Strained-Si nMOSFETs with a standard polysilicon gate process were fabricated down to 25 nm gate length with well-behaved characteristics and small difference in short channel effects. The performance enhancement degrades linearly as the gate length becomes shorter, due to not only the parasitic resistance but also heavy halo implant. Thus the key integration issues are how to manage threshold difference and As diffusion without excess doping. With comparable doping and well controlled parasitic resistance, up to 45% improvement in drive current is predicted for sub-50 nm gate length strained-Si nMOSFETs on the Si/sub 0.8/Ge/sub 0.2/ substrate. In this work approximately 45% enhancement is in fact demonstrated for 35 nm gate length devices, through advanced channel engineering and implementation of metal gates.