Integration of Nickel Monosilicide (NiSi) into an RIT SMFL NMOS Device

A nickel silicidation process has been developed for the Semiconductor & Microsystems Fabrication Laboratory (SM FL) at Rochester Institute of Technology (RIT). NISI and Ni2Si were obtained in doped source/drain and polysilicon gate regions respectively at rapid thermal annealing (RTA) condition of 500°C for 60 seconds. The sheet resistance of nickel silicide in both regions was measured to be 0.45Ω/o — 0.5Ω/o. Nickel silicide was also integrated into an RIT NMOSFET process where silicide was formed over the S/D and polysilicon gate regions. Rutherford Backscatter and x-ray diffraction data showed the formation of NiSi phase in the S/D region and Ni2Si in the polysilicon region. Preliminary electrical data from N1Si SID NMOS showed an increase in drain current by about 1.5 orders of magnitude, an increase in threshold current by 1 order of magnitude, a decrease in threshold voltage by 1/2 , and significantly better gate control

Development of nickel silicide for integrated circuit technology

Continuous advancements in devices, materials and processes have resulted in integrated circuits with smaller device dimensions, higher functionality and higher speed. The complementary metal oxide semiconductor (CMOS) technology has been the engine of this success. The MOS transistor is shrinking following the Moore\u27s Law over the last several decades. As the device dimensions are approaching nanometer regime, parasitic resistance, capacitance and inductance are beginning to influence the performance significantly. Self-aligned silicide process was developed in mid eighties that allowed reduction of gate and contact resistance by using metal silicides as low resistivity materials. The process also enabled higher packing density. Many silicides have been extensively studied and Titanium silicide (TiSi2) and Cobalt silicide (CoSi2) have been implemented into modern devices. With devices shrinking, TiSi2 and CoSi2 are finding serious limitations of linewidth effect and excessive silicon consumption. One attractive alternative is nickel monosilicide (NiSi). NiSi has comparable resistivity as traditional silicides yet consumes less silicon during formation, no line width dependence, single thermal treatment, and relatively planar silicide-silicon interface. However, implementation of NiSi into future generation devices has been delayed by limited knowledge of its thermal instability. In the study presented in this thesis, silicidation of nickel metal has been investigated. Silicidation has been carried out on doped and non-doped polycrystalline and crystalline silicon regions. Rapid thermal process was used for the silicidation of sputtered nickel metal into nickel silicide. The electrical and material properties of nickel silicide were characterized, and correlations between electrical data, material properties, and silicidation conditions have been made. Electrical resistivity was calculated through the uses of sheet resistivity measurements using the four-point probe technique and the grooving technique. The grooving technique was used to measure the silicide\u27s thickness necessary for electrical resistivity calculation. The silicide surface topography and phase composition were analyzed using the AFM and XRD technique respectively. Furthermore, RBS and SIMS analysis were done to complement the material properties study of nickel silicide. The experimental result showed strong correlation between nickel silicide\u27s electrical resistivity with surface topography and phase composition. A multiple phases mixture composition was observed in crystalline silicon and polysilicon regions at temperature less than 573°C and 695°C respectively. It is concluded that the most optimal silicidation condition for obtaining the single-phase nickel monosilicide was at 695°c for 60 sec. Such condition yield a NiSi film with an electrical resistivity of ~1.6 x 10-5 (Si), 3.3 x 10-5 Ω-cm (Poly). The most optimal silicidation for obtaining the lowest multi-phase mixture silicide was found to be at 500°C for 20sec or more. Such condition yielded a NixSi + NiSi phase mixture with an electrical resistivity of ~ 1.6 x 10-5 (Si), 2.5 x 10-5 Ω-cm (Poly)

Molecular mechanism of Inhibition of the CREB-coactivator TORC by the mitogen-activated kinase DLK in pancreatic beta-cells

Der ubiquitär exprimierte Transkriptionsfaktor CREB ist an zahlreichen zellulären Signaltransduktionswegen einschließlich der Regulation des Stoffwechsels, des Zellzyklus und überlebens, des Zellwachstums und der Immunregulation beteiligt. Drei Isoformen des Transducer of Regulated CREB (TORC) wurden kürzlich als weitere Kofaktoren von CREB identifiziert. Die Phosphorylierung von TORC2 am Ser-171 bzw. von TORC1 am Ser-167 führt zu einer Interaktion mit 14-3-3 Proteinen, wodurch TORC im Zytosol verbleibt. Die Dephosphorylierung dieser Aminosäuren resultiert in der nukleären Lokalisation von TORC, wo es mit dem homodimesierten Leuzin-Zipper von CREB interagiert und so die CREB-abhängige Gentranskription vermittelt. Eine frühere Untersuchung zeigte, daß die Dual Leucine Zipper Kinase DLK die durch Membrandepolarisation stimulierte CREB-abhängige Gentranskription in Beta-Zellen hemmte. Da die Rekrutierung von TORC notwendig für die volle transkriptionelle Aktivität von CREB ist, könnte TORC ein Ziel von DLK sein. In der vorliegenden Untersuchung wurde die Regulation von TORC durch die DLK untersucht. Hierzu wurde die Wirkung von DLK auf die transkriptionelle Aktivität von TORC in Beta-Zellen mittels Luciferasereportergenassays untersucht. Eine Interaktion zwischen DLK und TORC wurde durch in vitro Protein-Proteininteraktionsassays und Koimmunpräzipitation analysiert. Für die Untersuchungen zur Phosphorylierung von TORC durch DLK wurden Western Blot Analysen und in vitro Kinaseassays eingesetzt. Die Wirkung von DLK auf die nukleäre Translokation von TORC und die Rekrutierung an CRE enthaltende Promotoren wurde mittels immunzytochemischen Untersuchungen, Chromatinimmunpräzipitation und Luciferasereportergenassays untersucht. DLK hemmte die transkriptionelle Aktivität aller drei TORC Isoformen. Diese hemmende Wirkung war abhängig von der Fähigkeit DLK s zu homodimerisieren und von ihrer Kinaseaktivität. Der in vitro Kinase Assay zeigte, daß weder TORC1 noch TORC2 direkte Substrate der Kinase waren. Jedoch zeigte sich im Immunoblot, daß die Überexpression von DLK zu einer verstärkte Phosphorylierung von TORC1 am Ser-167 und an anderen nicht identifizierten Aminosäuren führte. Zusätzliche Behandlung der HIT Zellen mit einem Hemmstoff von JNK, einer der DLK untergeordneten Kinase, reduzierte die Phosphorylierung von TORC1 am Ser-167 und hob die langsamere Migration weiterer phospho-TORC1 Banden auf. Diese Daten lassen vermuten, daß DLK wahrscheinlich durch Aktvierung von JNK die Phosphorylierung von TORC induziert. Neben einer Phosphorylierung konnte mittels in vitro Protein-Protein Interaktionsassays und Koimmunpräzipitationen gezeigt werden, daß DLK mit TORC interagiert. Diese Interaktion war abhängig von der Fähigkeit DLK s zu homodimerisieren, da die DLK-PP Mutante in einem deutlich geringeren Ausmaß als DLK Wildtyp an das immobilisierte His-TORC Fusionsprotein band. Da DLK Wildtyp und seine Kinase-tote Mutante in demselben Ausmaß mit immobilisierten His-TORC Fusionsprotein interagierten, kann geschlossen werden, daß die Ausbildung eines Leuzin-Zippers notwendig für die DLK TORC Interaktion ist. Ebenfalls scheint die coiled-coil Stuktur, die durch die N-terminalen Domänen des TORC Tetramers gebildet wird, für die Interaktion mit dem Leuzin-Zipper von DLK erforderlich zu sein. In Abhängigkeit von seiner enzymatischen Aktivität verminderte DLK die nukleäre Lokalisation von TORC und die TORC-abhängige, CRE-dirigierte Gentranskription. Die Chromatinimmunpräzipitation zeigte, daß DLK die Rekrutierung von TORC an einen CRE enthaltenden Promotor verminderte. Zusammengefaßt zeigt die vorliegende Untersuchung, daß TORC ein Ziel der hemmenden Wirkung von DLK in Beta-Zellen ist. Die DLK induzierte Hemmung von TORC stellt einen neuen Signalweg dar, der durch Modifikation der CREB-abhängigen Gentranskription zur Regulation von Apoptose und Proliferation in Beta-Zellen beiträgt. Die Hemmung von DLK in Beta-Zellen könnte somit ein Ziel für die Therapie des Diabetes mellitus darstellen

THE EFFECTS OF HYDROSTATIC PRESSURE ON MBH4 (M = K, Na) STRUCTURES

In recent decades, a lot of efforts has been spent on investigation of metal borohydrides, which can potentially serve as advanced hydrogen storage materials for mobile applications. In this research, we investigate the structure changes under high pressure of the compounds MBH4 (M = K, Na) as important borohydrides in hydrogen technologies, using ABINIT simulation package based on density functional theory (DFT) and the generalized gradient approximation (GGA). The pressure is in a wide range of 0 GPa to 40 GPa. Structural analysis indicates the phase transformation in the examined range of pressure, which is evidenced by the interaction between metal cations and BH4-, interactive behavior of BH4 tetrahedron in the simulated cells, change of volume, distance between B and H ions, and enthalpy difference

Toward An IoT-based Expert System for Heart Disease Diagnosis

IoT technology has been recently adopted in the healthcare system to collect Electrocardiogram (ECG) signals for heart disease diagnosis and prediction. However, noises in collected ECG signals make the diagnosis and prediction system unreliable and imprecise. In this work, we have proposed a new lightweight approach to removing noises in collected ECG signals to perform precise diagnosis and prediction. First, we have used a revised Sequential Recursive (SR) algorithm to transform the signals into digital format. Then, the digital data is proceeded using a revised Discrete Wavelet Transform (DWT) algorithm to detect peaks in the data to remove noises. Finally, we extract some key features from the data to perform diagnosis and prediction based on a feature dataset. Redundant features are removed by using Fishers Linear Discriminant (FLD). We have used an ECG dataset from MIT-BIH (PhisioNet) to build a knowledge-base diagnosis features. We have implemented a proof-of concept system that collects and processes real ECG signals to perform heart disease diagnosis and prediction based on the built knowledge base

Robust Adaptive Controls of a Vehicle Seat Suspension System

This work proposes two novel adaptive fuzzy controllers and applies them to vibration control of a vehicle seat suspension system subjected to severe road profiles. The first adaptive controller is designed by considering prescribed performance of the sliding surface and combined with adaptation laws so that robust stability is guaranteed in the presence of external disturbances. As for the second adaptive controller, both the H-infinity controller and sliding mode controller are combined using inversely fuzzified values of the fuzzy model. In order to evaluate control performances of the proposed two adaptive controllers, a semi-active vehicle suspension system installed with a magneto-rheological (MR) damper is adopted. After determining control gains, two controllers are applied to the system and vibration control performances such as displacement at the driver’s position are evaluated and presented in time domain. In this work, to demonstrate the control robustness two severe road profiles of regular bump and random step wave are imposed as external disturbances. It is shown that both adaptive controllers can enhance ride comfort of the driver by reducing the displacement and acceleration at the seat position. This excellent performance is achieved from each benefit of each adaptive controller; accurate tracking performance of the first controller and fast convergence time of the second controller

Magnetorheological Fluid Based Devices Reported in 2013–2018: Mini-Review and Comment on Structural Configurations

This paper presents a mini-review of magnetorheological (MRF) fluid-based devices (MRF devices in short) including the brake, clutch, damper, and the mount reported from 2013 to 2018. MRF devices are usually designed based on three operating modes of MRF: flow mode, shear mode and squeeze mode. Each mode has its own characteristics for the high performance of application systems. Therefore, numerous design configurations of MRF devices have been proposed by many researchers. In this article, among many different MRF devices such as MRF brake, clutch, damper and MRF mount proposed over the last 6 years are examined in the sense of their structural configuration and operating principles. Certain advantages and demerits of each MRF device are also discussed. In addition, some useful design guidelines of MRF devices, which are absolutely different from developed MRF devices so far, are provided to enhance design simplicity and control performance

Exploiting secure performance of full-duplex decode and forward in optimal relay selection networks

In the presence of an illegitimate user, we investigate the secrecy outage probability (SOP) of the optimal relay selection (ORS) networks by applying decode-and-forward (DnF) based full-duplex (FD) relaying mode. The closed-form expressions for the allocations of the end-to-end signal-to-interference-plus-noise ratio (SINR) in each wireless network are derived as well as the closed-form expression for the exact SOP of the proposed ORS system is presented under Rayleigh fading schemes. As an important achievement, SOP is also compared between orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) schemes. Our results reveal that the SOP of the suggested scheme can be considerably influenced by several parameters involved, including the number of relays, the average signal-to-noise ratio (SNR) of eavesdropper links, transmit power and the average residual self-interference (SI) enforced on the FD relays.Web of Science244767