Replacement metal-gate NMOSFETs with ALD TaN/EP-Cu, PVD Ta, and PVD TaN electrode

This work reports the first replacement (damascene) metal gate NMOSFETs with atomic layer deposition (ALD) TaN/PVD and electroplated Cu as the stacked gate electrode. Transistors with PVD TaN and PVD Ta electrode are also fabricated. Our data show that ALD TaN has the right work function for the N-MOSFETs. The Cu damascene process can reduce the gate resistivity. The ALD process has the advantage of reducing the stress and radiation damage to the gate oxide. The damascene process flow bypasses high temperature steps (>600/spl deg/C)-critical for metal gate and high-k materials.     

Dynamics of fast dislocations

Plastic deformation of crystalline solids at ultra-high strain rates may involve dislocations moving at supersonic speeds, the feasibility of which has been demonstrated via molecular dynamics simulation. The motion of these dislocations in a crystal depends on the defects they encounter, which may slow, or even pin, them down. Recently, we have conducted a series of investigations on the dynamics of transonic dislocations during their interactions with other dislocations, small voids and small interstitial loops, using the molecular dynamics method. The results indicate that a transonic dislocation will be slowed down to subsonic speed by a subsonic dislocation in front of it, and that approaching dislocations at sufficiently high velocities may not form a stable dipole. Small defects, like voids and interstitial clusters, on the other hand, will only temporarily slow down a segment of the transonic dislocation, which absorbs the interstitial loop by forming jogs, and sweeps the void into a few smaller defects of vacancy type. Upon release from the clusters, this segment of dislocation regains speed and becomes transonic again. In view of the possible important role played by high-speed dislocations during high-speed deformation, and from the point of scientific interest, we summarize this series of investigations, and discuss their implications in the present paper.     

Microwave moisture measurement of grains

A two-parameter transmission technique is described for online, in situ measurement of the bulk moisture content of grains using microwaves. This noncontacting 4.9-GHz system is configured so that a well-collimated TEM beam is transmitted through a layer of grain, e.g., moving on a conveyer or flowing in a chute. The changes in attenuation and phase serve as two independent measurement parameters from which the wet and dry basis weights (grams per square centimeter) and moisture can be found using a linear model, independent of the layer thickness. If the layer thickness is also known, the wet and dry densities (grams per cubic centimeter) and complex dielectric constant can be found     

Reverse-order source/drain formation with double offset spacer (RODOS) for low-power and high-speed application

We proposed "reverse-order source/drain formation with double offset spacer" (RODOS) structure for low-power and high-speed applications. Both simulation and experimental data were used to evaluate the potential of the structure. It showed improved performance in terms of poly-depletion effect, dc characteristics, gate delay (CV/I), switching energy (CV/sup 2/) and linearity (V/sub IP3/). It satisfied all the requirements of LOP and LSTP for 90 nm technology node in ITRS 2002. Simulation predicted 794 /spl mu/A//spl mu/m in on-current, 0.1 nA//spl mu/m in off-current, 65 mV/V in DIBL, 80 mV/dec in SS, 1.29 ps in gate delay, 198 GHz in f/sub T/ and 0.151 fJ in switching energy in addition to enhanced linearity. Finally, we confirmed the high feasibility and potential of the RODOS MOSFET's for low-power and high-speed applications such as an LNA in portable communication appliances.     

Optimal redundancy resolution of a kinematically redundant manipulator for a cyclic task

This article proposes a method for the global optimization of redundancy over the whole task period in a kinematically redundant manipulator. The necessary conditions based on the calculus of variations for integral-type criteria result in a second-order differential equation. For a cyclic task, the boundary conditions for conservative joint motions are discussed. Then, we reformulate a two-point boundary value problem to an initial value adjustment problem and suggest a numerical search method based on the iterative optimization for providing a globally optimal solution using the gradient projection method. Since the initial joint velocity is parameterized with the number of redundancy, we only search parameter values in the parameterized space using the configuration error between the initial and final time. We show through numerical examples that multiple nonhomotopic extremal solutions satisfying periodic boundary conditions exist according to initial joint velocities for the same initial configuration. Finally, we discuss an algorithm for topological liftings of the paths and demonstrate the generality of the proposed method by considering the dynamics of a manipulator.     

用于锁模光纤激光陀螺的相敏检测

通过采用锁相放大器,演示了一种性能明显提高的锁模光纤激光陀螺.结果表明锁相放大器的输出与转动速率之间具有理想的线性关系,并对两脉冲(在时间间隔测量过程中引起相位误差)之间的光强差不敏感.与以往报道的时间间隔测量相比,演示了长期稳定性提高了二个数量级.     

Negative-differential transconductance characteristics at room temperature in 30-nm square-channel SOI nMOSFETs with a degenerately doped body

Negative-differential transconductance characteristics at room temperature with a peak-to-valley ratio of about two were observed in 30-nm square-channel silicon-on-insulator nMOSFETs with degenerately doped bodies. High channel-doping concentration creates the degeneracy in the p-type body of the self-aligned SOI MOSFET and consequently, enables band-to-band tunneling between degenerate body and source-drain. I/sub DS/-V/sub DS/ curves in the negative drain bias region also show band-to-band tunneling current as in the case of forward-biased p-n tunnel junctions.     

Influence of ZnCl2 on the structure and mechanical properties of polyacrylonitrile fibers

The structure and mechanical properties of polyacrylonitrile fibers containing small amounts of Zn²⁺ were investigated. It is possible to interpret the influence of ZnCl₂ on the fibers by diffusion. Fibers spun from spinning dope containing ZnCl₂ may have a denser and finer structure because ZnCl₂ in the spinning dope retards the coagulation rate. The tensile strength and modulus of the fibers are much improved because of the retardation of coagulation. It is probable that the complexation between Zn²⁺ and CN groups does not contribute to the improvement of the mechanical properties because the amount of ZnCl₂ added in a spinning dope is extremely small.