Anomalous Ti SALICIDE gate to source/drain shorts induced by dry Sietch during TiSi2 local interconnect formation

A new failure mode was observed in a 0.5 μm version of the silicided amorphous-silicon contact and interconnect (SAC) technology. Massive PMOS gate to source/drain shorts were found. The cause is attributed to formation of Ti during the Si etch. The fluorinated Ti surface fails to form adequate TiN diffusion barrier during subsequent rapid thermal annealing (RTA) in N₂ or NH₃ ambient. Si diffuses from the polycrystalline Si gate and/or the p-type source/drain onto the spacer, reacts with Ti and forms resistive leakage paths. A blanket low-dose, low-energy As implant prior to Ti deposition corrects this problem without adversely changing device characteristics     

A multivariate double EWMA process adjustment scheme for drifting processes

The “predictor-corrector” feedback controller, a process adjustment scheme proposed for semiconductor manufacturing run-to-run processes that drift, is extended to the multiple-input-multiple-output case. The controller is based on two coupled multivariate Exponentially-Weighted-Moving-Average (EWMA) equations, thus its performance depends on the choices of EWMA weight matrices. Stability conditions are given for a pure gain process adjusted with a MIMO double EWMA (EWMA) controller. It is shown that the stability conditions are invariant with respect to various realistic drift disturbance models. Recommendations on how to choose the EWMA weight matrices are given. An analysis is conducted to assess the impact of errors in the estimates of the process gains. The proposed MIMO EWMA feedback controller is compared to the common practice of using multiple single-input-single-ouput dEWMA controllers running in parallel.     

Analytical optical solution of the extension of the depth of field using cubic-phase wavefront coding. Part II. Design and optimization of the cubic phase

In this paper we use our derived approximate representation of the modulation transfer function to analytically solve the problem of the extension of the depth of field for two cases of interest: uniform quality imaging and task-based imaging. We derive the optimal result for each case as a function of the problem specifications. We also compare the two different imaging cases and discuss the advantages of using our optimization approach for each case. We also show how the analytical solutions given in this paper can be used as a convenient design tool as opposed to previous lengthy numerical optimizations.     

Electrostatic funneling for precise nanoparticle placement: a route to wafer-scale integration

We demonstrate a large-scale placement of nanoparticles through a scheme named "electrostatic funneling", in which charged nanoparticles are guided by an electrostatic potential energy gradient and placed on targeted locations with nanoscale precision. The guiding electrostatic structures are defined using current CMOS fabrication technology. The effectiveness of this scheme is demonstrated for a variety of geometries including one-dimensional and zero-dimensional patterns as well as three-dimensional step structures. Placement precision of 6 nm has been demonstrated using a one-dimensional guiding structure comprising alternatively charged lines with line width of approximately 100 nm. Detailed calculations using DLVO theory agree well with the observed long-range interactions and also estimate lateral forces as strong as (1-3) x 10(-7) dyn, which well explains the observed guided placement of Au nanoparticles.     

Middleware Architecture for Next Generation Heterogeneous Networks

In this paper we present a framework, called Futon, which provides a platform to integrate heterogeneous radio access networks. Futon is a hybrid fibre-radio network that replaces legacy base stations with simple remote antenna units, which are connected to a central unit. As a part of the Futon framework, a generic middleware architecture is discussed in detail, which provides interoperability, cooperative management and service provisioning to both underlying radio access networks (RANs) and IP layer for a heterogeneous network scenario. One of the middleware??s functionality is to provide vertical handover between heterogeneous IP-based radio access technologies and to ensure seamless mobility and service continuity, which is implemented on top of an IPv4/IPv6 Mobile IP (MIP) core. In this paper, the Futon framework and a generic middleware architecture as a part of Futon framework for heterogeneous RANs is discussed. The main modules of the middleware, namely common radio resource management (CRRM), media independent handover, Service/Connection Manager and link selection are explained in detail. Radio over fibre (RoF) Manager is an important part of Central unit, which does performance, fault and security management of network elements. RoF manager helps middleware during handoff, by providing the status of fibre optic links. The implementation of Security management module as a part of RoF manager, and results of authentication with AAA protocol are explained. The CRRM as part of middleware is simulated and the results of experimental evaluation are presented.     

CMOS-compatible fabrication of room-temperature single-electron devices

Devices in which the transport and storage of single electrons are systematically controlled could lead to a new generation of nanoscale devices and sensors. The attractive features of these devices include operation at extremely low power, scalability to the sub-nanometre regime and extremely high charge sensitivity. However, the fabrication of single-electron devices requires nanoscale geometrical control, which has limited their fabrication to small numbers of devices at a time, significantly restricting their implementation in practical devices. Here we report the parallel fabrication of single-electron devices, which results in multiple, individually addressable, single-electron devices that operate at room temperature. This was made possible using CMOS fabrication technology and implementing self-alignment of the source and drain electrodes, which are vertically separated by thin dielectric films. We demonstrate clear Coulomb staircase/blockade and Coulomb oscillations at room temperature and also at low temperatures.     

Hierarchically porous nanoarchitecture constructed by ultrathin CoSe2 embedded Fe-CoO nanosheets as robust electrocatalyst for water oxidation

The sluggish kinetics and high cost of the noble-metal based electrocatalyst for oxygen evolution reaction(OER)still seriously limits the efficiencies of water splitting.Herein,for the first time,we rationally design a porous hierarchical nanoarchitecture,constructed by ultrathin CoSe2 embedded Fe-CoO nanosheets(CoSe2@Fe-CoO),which is synthesized via self-assembly hydrolysis driven in-situ synergetic selenization of Fe/Co/O/Se precursor followed by Ostwald ripening.As an OER catalyst,the porous CoSe2@Fe-CoO hybrid with abundant CoOOH electroactive sites delivers a small Tafel of 56.2 mV/dec with very low onset overpotential of 280 mV@10 mA/cm2 and excellent long-term physicochemical stability till 62 h without obvious decay,which outperforms well-established benchmark electrocatalysts(RuO2).The boosted OER performance of CoSe2@Fe-CoO nanosheets is mainly attributed to its iron-doping effect,porous nanoarchitecture,and multicomponent synergetic/interfacial effect between ultrathin cobalt(Ⅱ)oxide and conductive cobalt selenide(CoSe2)nanoframework.This work presents a facile construction strategy to find a nonprecious hybrid OER electrocatalyst with excellent performance and long-term stability.     

Thermal Performance Investigation of Mechanical Draft Cooling Tower Using Psychrometric Gun Technique

This paper presents an experimental work that studies the performance of a counterflow cooling tower with expanded wire mesh packing. Due to complicated configuration of the expanded wire mesh packing surface, it is not possible to measure the temperature of the air in the intermediate section of the cooling tower, but only that of the exit air and water temperature. In the experimental study a new concept of psychrometric gun technique is used to measure dry/wet bulb temperature of air at intermediate points of tower packing. First, the paper elaborates on the effect of atmospheric conditions, water mass flow rate and inlet temperature on the variation of the thermodynamics properties of moist air inside the cooling tower and thermal performance characteristics. Second, exergy analysis is applied to study the cooling tower potential of performance using the psychrometric gun technique. An analytical model was compared with experimental data.     

Electrical conductivity of thermally grown titanium oxide films

TheV-I characteristics of thermally grown titanium oxide films on titanium are described and are explained using a model for current transport in the films.     

A join algorithm for combining AND parallel solutions in AND/OR parallel systems

When two or more literals in the body of a Prolog clause are solved in (AND) parallel, their solutions need to bejoined to compute solutions for the clause. This is often a difficult problem in parallel Prolog systems that exploit OR and independent AND parallelism in Prolog programs. In several AND/OR parallel systems proposed recently, this problem is side-stepped at the cost of unexploited OR parallelism in the program, in part due to the complexity of the backtracking algorithm beneath AND parallel branches. In some cases, the data dependency graphs used by these systems cannot represent all the exploitable indenpendent AND parallelism known at compile time.In this paper, we describe the compile time analysis for an optimizedjoin algorithm for supporting independent AND parallelism in logic programs efficiently without leaving any OR parallelism unexploited. We then discuss how this analysis can be used to yield very efficient runtime behavior. We also discuss problems associated with a tree representation of the search space when arbitrarily complex data dependency graphs are permitted. We describe how these problems can be resolved by mapping the search space onto the data dependency graphs themselves. The algorithm has been implemented in a compiler for parallel Prolog based on the Reduce-OR process model. The algorithm is suitable for the implementation of AND/OR systems on both shared and nonshared memory machines. Performance on benchmark programs exhibiting AND and OR parallelism on one shared memory machine and one message passing machine is presented.This work was supported in part by NSF Grants CCR-87-00988 and CCR-89-02496.A shorter version of this paper appears in theProceedings of NACLP 1990.