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The muscle synergy hypothesis assumes that the nervous system controls muscles in groups to simplify behavioral tasks, which makes it possible for modularizing motor function assessment. This paper presents a new assessment method based on muscle synergy space (MSS) model to evaluate motor functions after stroke. It consists of spatiotemporal feature module, muscle activation module and synergy activation module, and focuses on the spatial and temporal characteristics of muscle synergies via synergy vectors and activation coefficients. We further applied this method to reveal spatial and temporal characteristics difference of muscle synergy between healthy controls and stroke patients. The effectiveness and accuracy of MSS model were proved by significant positive correlations between Fugl-Meyer score and the total number of optimal synergies of three modules. This measurement methodology could serve as a quantitative indicator for motor function and provide more scientific rehabilitation guidance. [ABSTRACT FROM AUTHOR]

With the increased demands of human-machine interaction, haptic feedback is becoming increasingly critical. However, the high cost, large size and low efficiency of current haptic systems severely hinder further development. As a portable and efficient technology, cutaneous electrotactile stimulation has shown promising potential for these issues. This paper presents a review on and insight into cutaneous electrotactile perception and its applications. Research results on perceptual properties and evaluation methods have been summarized and discussed to understand the effects of electrotactile stimulation on humans. Electrotactile applications are presented in categories to understand the methods and progress in various fields such as prostheses control, sensory substitution, sensory restoration and sensorimotor restoration. State of the art has demonstrated the superiority of electrotactile feedback, its efficiency and its flexibility. However, the complex factors and the limitations of evaluation methods made it challenging for precise electrotactile control. Groundbreaking innovation in electrotactile theory is expected to overcome challenges such as precise perception control, information capacity increasing, comprehension burden reducing and implementation costs. [ABSTRACT FROM AUTHOR]

Brain networks allow a topological understanding into the pathophysiology of stroke-induced motor deficits, and have been an influential tool for investigating brain functions. Unfortunately, currently applied methods generally lack in the recognition of the dynamic changes in the cortical networks related to muscle activity, which is crucial to clarify the alterations of the cooperative working patterns in the motor control system after stroke. In this study, we integrate corticomuscular and intermuscular interactions to cortico-cortical network and propose a novel closed-loop construction of cortico-muscular-cortical functional network, named closed-loop network (CLN). Directional characteristic in terms of differentiating causal interactions is endowed on basis of the CLN framework, further expanding the definition of functional connectivity (FC) and effective connectivity (EC) dedicated to CLN. Next, CLN is applied to stroke patients to reveal the underlying after-effects mechanism of low frequency repetitive transcranial magnetic stimulation (rTMS) induced alterations of cortical physiologic functions during movement. Results show that the short-term modulation of rTMS is reflected in the enhancement of information interaction within the interhemispheric primary motor regions and inhibition of the coupling between motor cortex and effector muscles. CLN provides a new perspective for the study of motor-related cortical networks with muscle activities involvement instead of being restricted to brain network analysis of behaviors. [ABSTRACT FROM AUTHOR]

Serious agglomeration of ultrathin TiSix employed in source–drain (S–D) ohmic contacts after high-temperature annealing was manifested in previous work. This severely restricts its application in state-of-the-art DRAM peripheral 3-D FinFET transistors. In this work, the effects of hafnium (Hf) interlayer on the thermal stability of ultrathin TiSix in TiSix/n+-Si ohmic contacts were systematically studied. As-prepared ultrathin TiSix and TiSix/n+-Si ohmic contacts with 0-, 1-, 2-, and 3-nm Hf interlayers were characterized by means of specific contact resistivity ($\rho _{\text {c}}$), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). It is found that compared to the counterparts with 0-, 2-, and 3-nm Hf, the presence of 1-nm Hf interlayer is proven to be effective in enhancing the thermal stability of ultrathin TiSix significantly. With 1-nm Hf, amorphous HfO2, and Hf silicate are readily formed, which hinders the interdiffusion between Ti and Si atoms and resultant agglomeration of ultrathin TiSix films. This is thought to be responsible for such a remarkably enhanced thermal stability of ultrathin TiSix in TiSix/n+-Si ohmic contacts. [ABSTRACT FROM AUTHOR]

Objective: While neuroplasticity and functional reorganization during motor recovery can be indirectly reflected and evaluated by functional corticomuscular coupling (fCMC), little work has been published regarding the cortical origin of abnormal muscle synergy and compensatory mechanism in the separation movement of stroke patients. Methods: In this study, we proposed to use extended partial directed coherence (ePDC) combined with an optimal spatial filtering approach to estimate fCMC in stroke patients and healthy controls, and further established muscle synergy model (MSM) to jointly explore the modulation mechanism between cortex and muscles. Results: Compared to healthy controls, stroke patients had significantly reduced coupling strength in both descending and ascending pathway. Moreover, the MSM were abnormal with high variability and low similarity in the separation stage of stroke patients. Further exploration of the positive relationship between fCMC characteristics and MSM parameters proved the possibility of using fCMC-MSM-based correlation indicator to evaluate abnormality of the cortical related synergy movement as well as the rehabilitation level of stroke patients. Conclusion: We developed a computational procedure to evaluate the correlation between fCMC and MSM in stroke patients. Significance: This article provides a quantitative evaluation metrics based on fCMC to reveal the deficits during poststroke motor restoration and a promising approach to help patients correct abnormal movement habits, paving the way for neurophysiological assessment of neuromuscular control in conjunction with clinical scores. [ABSTRACT FROM AUTHOR]

Due to extremely tight Contacted Poly Pitch (CPP) in sub-10 nm nodes, specific contact resistivity ($\rho _{{\text {c}}}$) has become the main concern for further improvement of transistor performance. Both the reduction of Schottky barrier heights (SBHs) and the enhancement of surface dopant concentration ($\text{N}_{{\text {s}}}$) are considered as the most effective approaches to reduce $\rho _{{\text {c}}}$. In this work, a novel in-situ steam generation (ISSG) oxidation process prior to Ti silicidation is proposed to achieve an enhanced $\text{N}_{{\text {s}}}$ value, thanks to the segregation of P at the surface of $\text{n}^{+}$ -Si. Refined Transmission Line Model (RTLM) structures were fabricated to extract the $\rho _{{\text {c}}}$ accurately and reliably. The dopant redistribution of P was characterized by both secondary ion mass spectrometry (SIMS) and spreading resistance probe (SRP). Compared to control samples, the $\rho _{{\text {c}}}$ value for samples with 4 nm ISSG SiO2 is reduced from ${2.91}\times {10}^{-{8}}$ to ${1.90}\times {10}^{-{8}} \Omega $ -cm2, and this is attributed to the enhancement of $\text{N}_{{\text {s}}}$ value. [ABSTRACT FROM AUTHOR]

The impact of As preamorphization implant (PAI) on specific contact resistivity (ρc) is investigated for Ti-based Ohmic contacts on n+-Si in this article. The ρc value of TiSix/n+ −Si contacts is greatly improved with low-dose As PAI whereas this improvement is impaired with increased dose of As PAI. The ρc results from the joint effort of the reduction of effective Schottky barrier height (SBH) to electrons (φbn,eff) , retardation of Ti silicidation, and annihilation of end-of-range (EOR) defects. Besides, the interfacial microstructures of TiSix/n+ −Si affect ρc, correlated with the post metal anneal (PMA). [ABSTRACT FROM AUTHOR]

Ultrathin Ni germanosilicide liner (<50 Å) is employed in advanced pMOS contact metallization in this work. Due to the intrinsic high work function, the NiSixGey/p+-SiGe:B contacts show improved specific contact resistivity (ρc) with respect to conventional TiSixGey/p+-SiGe:B ones. It is further demonstrated that the ρc of NiSixGey/p+-SiGe:B contacts is correlated with both Ni thickness and post metal anneal (PMA). Utilizing Ge preamorphization implant (Ge PAI) followed by B ion implant (B I/I), the active concentration of B dopants is enhanced from 1 × 1020 cm−3 for reference to 6× 1020 cm−3. Consequently, a remarkably lowered ρc of ~ 7.42× 10−9 Ω ⋅ cm2 is achieved for NiSixGey/p+-SiGe:B contacts, where Ni layer is 20 Å and PMA temperature is 500 °C. [ABSTRACT FROM AUTHOR]

As preamorphization implant (PAI) for Ti-based ohmic contacts on n+-Si is explored in this article. With As implantation at 3 keV/5 × 1013 cm−2, the specific contact resistivity (ρc) of TiSix on 1.4 × 1020 cm−3 P-doped (Nd) n+-Si is significantly reduced by ~33.8%, down to ~2.33 × 10−8-cm−2. This ρc improvement is a result of manipulation between the reduction of effective Schottky barrier height to electrons (φbn,eff) and the retardation of Ti silicidation, which are both strongly correlated with As segregation. In comparison with the widely adopted Ge PAI, As PAI shows superior performance for nMOS contact engineering, featuring with lower ρc and φbn,eff as well as better thermal stability. [ABSTRACT FROM AUTHOR]

This paper proposed, for the first time, that the band-edge effective work functions (EWFs) are achieved by employing PH3 plasma doping (PLAD) TiN metal gate for nMOS device application under replacement metal gate and high dielectric constant (k) dielectric/metal gate last nMOS device. The effects of PLAD energy, dose, gas mixture, and postdoping cleaning procedure on the EWF, EOT, and properties of TiN/HfO2/ILSiO2 gate-stack are investigated; the corresponding possible mechanisms are discussed. Suitable low threshold voltages of nMOSFETs are obtained, while shrinking the EOT. It reduces the corner effect on trench gate doping uniformity, which is induced by shadowing effect in the beam-line implantation technology, to a minimum. It has the potential for the further aggressively scaled 3-D CMOS device and beyond application. [ABSTRACT FROM AUTHOR]

This brief explores the specific contact resistivity ( \rho c ) of NiGe/n- and p-Ge contacts with and without carbon pregermanidation implantation. It is found that in the presence of carbon, not only the thermal stability of NiGe films is improved, but also the \rho c of the NiGe/n- and p-Ge contacts is reduced remarkably due to enhanced phosphorus (P) and boron (B) dopant segregation (DS) at the NiGe/Ge interface after nickel germanidation. At 500 °C germanidation temperature, the \rho c values are reduced from 1.1 \times 10^\mathrm -4 ~ \Omega -cm2 and 2.9 \times 10^-5 ~ \Omega -cm2 for NiGe/n- and p-Ge contacts without carbon to 7.3 \times 10^-5 ~ \Omega -cm2 and 1.4 \times 10^-5 ~ \Omega -cm2 for their counterparts with carbon, respectively. [ABSTRACT FROM AUTHOR]

This paper proposed, for the first time, that the dual band-edge effective work functions are achieved by employing a single metal gate (MG) and single high- $k$ (HK) dielectric via ion implantation into a TiN MG for HP CMOS device applications under a gate-last process flow. The P/BF2 ion-implanted TiN/HfO2/ILSiO2 gate-stack does not degrade the gate leakage, reliability, and carrier mobility, and reduces the effective oxide thickness. The impact of P/BF2 ion implant energy, dose, and TiN gate thickness on the properties of implanted TiN/HfO2/ILSiO2 gate-stack is studied, and the corresponding possible mechanisms are discussed. This technique has been successfully applied to the replacement MG and HK/MG last process flow to fabricate HP CMOSFETs and CMOS 32 frequency dividers with a minimum gate length of 25 nm. [ABSTRACT FROM PUBLISHER]

We present and demonstrate a self-aligned pocket well (SPW) structure used in planar bulk MOSFETs with a metal gate length of 25 nm and an effective channel length less than 20 nm. The SPW features a retrograde doping profile in vertical direction and a doping profile self-aligned with drain/extension in lateral direction. A novel process, called replacement spacer gate (RSG), is designed to avoid challenges in gate patterning and high- k metal gate filling. Planar bulk pMOSFETs, with SPW and halo doping, respectively, were simulated and fabricated adopting the RSG process. Due to its retrograde feature, the SPW can achieve low drain-induced barrier lowering (DIBL) along with low V_{T} . Compared with halo doping with the same V_{{T,{\rm sat}}} at VDD = 0.8 V, despite no I\mathrm{{\scriptscriptstyle ON}} enhancement, the SPW reduces DIBL by 45% and enhances IEFF by 18%. Compared with halo doping with the same I\mathrm{{\scriptscriptstyle OFF}} = 100 nA/ \mu \textm at V_{\rm DD} = 0.8 V, the SPW structure reduces DIBL by 16%, enhances I\mathrm{{\scriptscriptstyle ON}} by 5%, and improves IEFF by 30%. In addition, with the self-aligned feature, the SPW does not deteriorate junction band-to-band tunneling (BTBT) leakage in comparison with halo doping. Otherwise, 20 times larger BTBT leakage will emerge due to the profile overlap between retrograde doping and drain/extension doping. [ABSTRACT FROM AUTHOR]

This letter investigates the mitigation of reverse short-channel effect (RSCE) using multilayer atomic layer deposition (ALD) TiN/PVD Ti/CVD TiN metal gates (MG) for the p-channel metal–oxide–semiconductor field-effect transistors fabricated the by gate-last process. It is found that work function (WF) of multilayer ALD titanium nitride/physical vapor deposition titanium/chemical vapor deposition titanium nitride (ALD TiN/PVD Ti/CVD TiN) MG in devices of short channels is larger than in devices of long channels. This mainly results from different ALD TiN crystal orientations for devices with different gate lengths, that is, TiN(100) for devices with short gate length, whereas TiN(111) for devices with long gate length. The WF of ALD TiN(100) is larger than TiN(111). Meanwhile, because of the property of PVD sputtering, the Ti layer is thinner in devices of short channels than in devices of long channels. Our results on MOSCAP show that the flat-band voltage ( \(V_{\!fb}\) ) for TiN MG with a Ti layer is reduced by 0.2 V. Taking all the aforementioned into account, \(V_{th}\) roll-up is suppressed as the gate length shrinks, leading to the mitigation of RSCE. [ABSTRACT FROM PUBLISHER]