Influence of series resistance in oxide parameter extraction data from accelerated tests

Accelerated reliability tests on thin oxide capacitors can be affected by series resistance effects at high stress conditions. The purpose of this work is to point out such problems both with measurements and simulations. It is shown that breakdown electric field is overestimated. Due to the resulting nonuniform stress, charge to breakdown density is underestimated if the test structure layout is not accurately designed. In any case the series resistance effects can have an undesirable impact on the reliability evaluation of thin dielectrics.     

Gain equalization by mitigating self-filtering effect in a chain ofcascaded EDFA's for WDM transmissions

A simple method of alternatively using high-inversion and moderate-inversion erbium-doped fiber amplifiers (EDFA's) in an optical amplifier chain is presented to mitigate the self-filtering effect and equalize both signal power and signal-to-noise ratio (SNR) of multiple wavelength channels in wavelength-division multiplexing (WDM) transmission systems. The performance of the compensated system with alternatively used high- and moderate-inversion amplifiers is compared with the uncompensated ones where only moderate- or high-inversion amplifiers are employed. The result shows that the compensated system has a flatter gain profile, a lesser signal power spread, and SNR degradation     

Fourier-transform-limited pulses from gain-switched distributed-Bragg-reflector lasers using simultaneous modulation of gain and phase sections

Fourier-transform-limited pulses ( Delta tau . Delta nu approximately=0.35) have been obtained from a microwave-modulated DBR laser at 1.56 mu m. The chirp of the gain-switched pulse is compensated for by applying a fraction of the microwave signal to the phase section, thereby creating an instantaneous frequency shift of opposite sign. The generation of short coherent pulses from such a monolithic source can be of great interest for long haul soliton transmission.<>     

Performance of interface engineeredSiNx/ICL/InP/In0.53Ga0.47As/InP dopedchannel HIGFET's

SiN_x/InP/InGaAs doped channel passivated heterojunction insulated gate field effect transistors (HIGFETs) have been fabricated for the first time using an improved In-S interface control layer (ICL). The insulated gate HIGFETs exhibit very low gate leakage (10 nA@V_GS =±5 V) and I_DS (sat) of 250 mA/mm. The doped channel improves the DC characteristics and the HIGFETs show transconductance of 140-150 mS/mm (L_g=2 μm), f_t of 5-6 GHz (L_g=3 μm), and power gain of 14.2 dB at 3 GHz. The ICL HIGFET technology is promising for high frequency applications     

Analysis and design-optimization of LCC resonant inverter forhigh-frequency AC distributed power system

The analysis and design of an LCC resonant inverter for a 20 kHz AC distributed power system are presented. Several resonant converter topologies are assessed to determine their suitability for high efficiency power conversion, under resistive and reactive loads. Two LCC-resonant inverter designs were implemented. One with all switches operating with zero voltage switching (ZVS), and another with two switches operating with ZVS and two switches with zero current switching (ZCS). The experimental results are presented along with a performance comparison of the two versions     

Electrical passivation in hydrogen plasma exposed GaN

Lightly p-doped (3×10¹⁷ cm^-3) GaN grown on GaAs substrates by metal organic molecular beam epitaxy (MOMBE) shows deactivation of the residual acceptors on exposure to a microwave (2.45 GHz) hydrogen plasma at 250°C. Subsequent annealing to 350°C produces further dopant passivation, while higher temperatures (450°C) restore the initial conductivity. These results suggest that hydrogen carrier gases should be avoided during vapour phase growth of III-V nitrides     

Matrix effects in the determination of butyltin compounds in environmental samples by GC AA after hydride generation

Experiments for the determination of mono-, di and tri-butyltin (MBT, DBT and TBT) by hydride generation/gas chromatography/atomic absorption spectrometry in various matrices (sediment, suspended matter, mussel, algae and water) have revealed that poor butyltin recoveries are obtained in sediments displaying high sulphur and hydrocarbon contents; very poor recoveries were also observed for TBT in sediments with high chlorophyll pigment contents as well as in algal samples. It was however not clear whether the hydride generatin was inhibited by these infering compounds, as was previously assumed in the case of hydrocarbons, or whether interferences affected the atomization rate. Further studies were performed to solve this problem in order to validate this method in the case of analyses of, for example, oil-contaminated sediment and algae. This paper presents the results obtained. It is concluded here that the poor recoveries were due to an inhibition of hydride generation rather than to interference at the atomization stage.     

X-ray diffraction study of 'side-on fixed' homopolysiloxanes from nematic to smectic C phases

The X-ray patterns for the nematic phase in a series of side-on fixed polysiloxanes show different kinds of diffuse elements which imply complex short range ordering. A systematic structural study of the evolution of the patterns versus two molecular parameters, namely the spacer length and the length of the terminal aliphatic tails, suggests the possible occurrence of a smectic C phase for certain values of these parameters. Taking into account these tendencies, new synthesis led to a nematic-smectic C polymorphism observed for the first time in side-on fixed polysiloxanes.     

Temperature and modulation characteristics of resonant-cavitylight-emitting diodes

Resonant-cavity light-emitting diodes (RCLED) are novel, high-efficiency light-emitting diodes which employ optical microcavities. These diodes have higher intensities and higher spectral purity as compared to conventional LEDs. Analytical formulas are derived for the enhancement of the spontaneous emission along the optical axis of the cavity. The design rules for high-efficiency operation of RCLEDs are established. The temperature dependence of the emission intensity is analyzed in the range 20-80° and it is described by an exponential dependence with a characteristic temperature of 112 K. The modulation characteristics of RCLEDs exhibit 3 dB frequencies of 580 MHz. Eye diagrams at transmission rates of 622 Mb/s are wide open indicating the suitability of RCLEDs for high-speed data transmission