A simple method for extracting average doping concentration in thepolysilicon and silicon surface layer near the oxide in polysilicon-gateMOS structures

The author demonstrates a simple technique that extracts average doping concentration in the polysilicon and silicon near the oxide in a metal/polysilicon/oxide/silicon system. The technique is based on the maximum-minimum capacitance method on two large area structures-one MOSFET and one MOSC (MOS capacitor). The technique is simple and reliable since only three data points in the C-V data are required-two points in MOSC C-V and one point in MOSFET C-V. The technique avoids inaccuracy caused by interface traps at the polysilicon/oxide and the oxide/silicon interface. The technique can be implemented into fab routine electric-test procedures for simultaneously monitoring change of doping concentration in polysilicon and silicon during process development     

Enhancing the brightness of thin-film electroluminescent displaysby improving the emission process

AC thin film electroluminescent (ACTFEL) devices emit light laterally in addition to conventional surface emission. Because of the waveguiding in ACTFEL devices, lateral emission is stronger than surface emission. However, the former is ignored for displays. This note demonstrates that mirrors can be fabricated into substrates to reflect upward the lateral emission, which can then be summed with surface emission for displays. Use of standard silicon and thin film technology has demonstrated that the reflected lateral emission is a factor of three brighter than conventional surface emission. hence the effective efficiency of out-coupling the light has been improved for an ACTFEL device     

The Properties of Voronoi Tessellations for 2D Ising Fluid Near the Second-Order Magnetic Phase Transition

The topological and geometrical properties of Voronoi cells generated for 2D fluid of hard disks with Ising-like spins near the second-order phase transition from the paramagnetic to ferromagnetic phase are described for different disk densities. The comparison with Voronoi cells generated for the random hard disk system is given.     

Design for concurrent error detection and testability instorage/logic arrays

Storage/Logic Arrays (SLA's) represent a structured logic array approach to the design of VLSI sequential logic. Design for concurrent error detection and testability is complicated in these arrays by the presence of embedded memory elements and multiple levels of logic. A means of designing SLA's for ease of testability and concurrent error detection (CED) is provided in this paper. Test sets for static and dynamic CMOS circuits are described. Fault and error coverage is presented and performance and area costs are analyzed for example circuits. In addition, a means of implementing dynamic CMOS SLA's is presented and shown superior to previous NMOS, static CMOS, and dynamic CMOS approaches based upon power consumption and simplicity of design     

Smart cars, smart highways

Advanced electronics is being used to unclog the transportation network and allow private vehicles, trucks, buses and trains to move further faster. already a range of technologies and ideas have been explored, deployed, and tested as part of the Intelligent Vehicle Highway System programs in the United States and Japan, and in the Road Transport Informatics program in Europe. The authors describe how these latest electronics for automobiles and roadways herald far fewer traffic jams, greater safety, and perhaps even a decline in pollution     

Comment on raindrop size distribution model

The parameter set for the exponential raindrop size distribution model presented by Yeo, Kooi and Leong (see ibid. vol.41, P.709, 1993) was derived using a data set measured in Singapore. A limitation to the model is that it is accurate only for small rain rate or when the rain medium consists predominantly of small droplets with diameter D is < λ/π . A new parameter set that enables accurate computation of rain attenuation for droplets with diameter D = λ/π has since been derived using the same data set. This new parameter set has been proven to be more accurate in the computation of rain attenuation     

Compact conical antennas for wide-band coverage

A broadband antenna with a vertically polarized, omnidirectional electric field is studied. The design of the antenna and its feeding system in the wide frequency range from 20 to 1000 MHz is described and the driving-point impedance determined. Also calculated are the voltage standing-wave ratio (VSWR) and the input impedance of a transmission line connected to the antenna. More efficient operation at low frequencies is obtained by adding a length of transmission line to form a resonant section with the antenna. The effect of the different properties of the earth's surface on the field pattern is treated in a companion paper     

An electromigration failure model for interconnects under pulsedand bidirectional current stressing

An electromigration failure model which can be used to project the electromigration lifetime under pulsed DC and AC current stressing has been reported. The experimental results indicate that different metallization systems (Al-2%Si, Al4%Cu/TiW, and Cu) show similar failure behaviors, which can be explained and predicted by this model. The pulsed DC lifetime is found to be longer than DC lifetime, and the AC lifetime is found to be very much longer. This recognition can provide significant relief to circuit designs involving metals carrying pulsed DC and AC currents, and allow a more aggressive design to improve circuit density and speed     

InGaAs/AlAs/InGaAsP resonant tunneling hot electron transistorsgrown by chemical beam epitaxy

InP-based resonant tunneling hot electron transistors (RHET's) were studied systematically using chemical beam epitaxy (CBE) for the first time. All the RHET's studied have a highly strained AlAs/In_0.75Ga_0.25As/AlAs resonant tunneling double barrier as a hot electron injector, and an InP collector barrier with or without InGaAsP graded layers. The highest transport ratio (α) observed is 0.98, and the highest peak-to-valley current ratios (PVR's) measured are 20 and 200 in the collector current and base current, respectively, at 80 K. A self-consistent simulation is used as a reference to optimize the hot electron injector and to explain the ballistic transport. An energy spectrometer technique was applied to the RHET's for resolving the hot electron energy distribution which showed a full width at half maximum (FWHM) of around 58 meV, indicating ballistic transport of electrons. Finally, room temperature transistor action was also observed with a β of 4 and a cutoff frequency of 31 GHz     

Finite element computation of electromagnetic fields [hyperthermiatreatment]

A three dimensional finite element solution scheme is developed for numerically computing electromagnetically induced power depositions. The solution method is applicable to those problems for which it can be reasonably assumed that the magnetic permeability is homogeneous. The method employs an incident field/scattered field approach where the incident field is precalculated and used as the forcing function for the computation of the scattered field. A physically logical condition is used for the numerical boundary conditions to overcome the fact that electromagnetic problems are generally unbounded (i.e., the boundary condition is applied at infinity) but numerical models must have a boundary condition applied to some finite location. At that numerical boundary, an outgoing spherical wave is simulated. Finally, an alternate to a direct solution scheme is described. This alternate method, a preconditioned conjugate gradient solver, provides both a storage and CPU time advantage over direct solution methods. For example, a one-thousand fold decrease in CPU time was achieved for simple test cases. Unlike most iterative methods, the preconditioned conjugate gradient technique used has the important property of guaranteed convergence. Solutions obtained from this finite element method are compared to analytic solutions demonstrating that the solution method is second-order accurate