Design and simulation of optoelectronic oscillator with micro ring resonator and radio frequency amplifier modelling at 110 GHz

There is an increasing need for high performance oscillators as the faster transmission networks demand for high frequency signals. Opto-electronic oscillators (OEO) enable us to make better oscillators in terms of size, weight and power. In this paper, photonic integration is proposed for realizing the OEO with micro ring resonator (MRR) and radio-frequency (RF) amplifiers of monolithic microwave integrated circuit (MMIC), which can be used for generating 110 GHz sine wave. The OEO architecture is proposed and block diagram developed considering Silicon based MRR and three-stage RF amplifier based on GaN high-electron-mobility transistor (HEMT). A simulation model is developed according to the Klein model of MRR and is validated against the calculated performance parameters. MRR dimensions are calculated as with silicon on insulator (SOI) technology and a radius 5.27 μm for the device is derived. Free spectral range (FSR) of 48.52 nm and filter rejection ratio of 16.79 dB are obtained for this device. The proposed RF amplifier is modelled with GaN parameters derived from high frequency pinch-off model and with power amplifier considerations. The gain for this amplifier is obtained as 10.6 dB. The OEO design is developed in this project in such a way that the system can be manufactured with the existing methods.     

雪崩PIN二极管中的电流丝运动

The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations.The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered.The voltage waveform varies periodically due to the motion of the filament.The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates.Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction,it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.     

Micro-vibration parameters fast demodulation algorithm and experiment of self-mixing interference

Self-mixing interference （SMI） technique can be used for measuring vibration, displacement, velocity and absolute distance. In this paper, a simple demodulation algorithm for fast measuring frequency and amplitude of a simple harmonic vibration target is proposed based on the basic theoretical model of self-mixing interference effects. The simulative results show that the error between the vibration parameters which are demodulated by this algorithm and initial settings merely results from the sample rate. Further, the experimental system of self-mixing vibration measurement is built. The experimental results have a good agreement with simulation analyses. The maximum error of frequency demodulation is less than 1 Hz in our experiment.     

An improved temperature-dependent large signal model of microwave GaN HEMTs

Accurate modeling of the electrothermal effects of GaN electronic devices is critical for reliability design and assessment. In this paper, an improved temperature-dependent model for large signal equivalent circuit modeling of GaN HEMTs is proposed. To accurately describe the thermal effects, a modified nonlinear thermal sub-circuit which is related not only to power dissipation, but also ambient temperature is used to calculate the variations of channel temperature of the device; the temperature-dependent parasitic and intrinsic elements are also taken into account in this model. The parameters of the thermal sub-circuit are extracted by using the numerical finite element method. The results show that better performance can be achieved by using the proposed large signal model in the range of -55 to 125℃ compared with the conventional model with a linear thermal sub-circuit.     

Concerning the maximum frequency limits of Gunn operators

The length of the transit region of a Gunn diode determines the natural frequency at which it operates in fundamental mode－the shorter the device, the higher the frequency of operation. The long-held view on Gunn diode design is that for a functioning device the minimum length of the transit region is about 1.5 μm, limiting the devices to fundamental mode operation at frequencies of roughly 60 GHz. The authors posit that this theoretical restriction is a consequence of limits of the hydrodynamic models by which it was determined. Study of these devices by more advanced Monte Carlo techniques, which simulate the ballistic transport and electron-phonon interactions that govern device behaviour, offers a new lower bound of 0.5 μm, which is already being approached by the experimental evidence shown in planar and vertical devices exhibiting Gunn operation at 0.6 μm and 0.7 μm. It is shown that the limits for Gunn domain operation are determined by the device length required for the transferred electron effect to occur(approximately 0.15 μm, which as demonstrated is largely field independent) and the fundamental size of the domain(approximately 0.3 μm). At this new length, operation in fundamental mode at much higher frequencies becomes possible－the Monte Carlo model used predicts power output at frequencies over 300 GHz.     

Potentiality of semiconducting diamond as the base material of millimeter-wave and terahertz IMPATT devices

An attempt is made in this paper to explore the potentiality of semiconducting type-IIb diamond as the base material of double-drift region（DDR） impact avalanche transit time（IMPATT） devices operating at both millimetre-wave（mm-wave） and terahertz（THz） frequencies. A rigorous large-signal（L-S） simulation based on the non-sinusoidal voltage excitation（NSVE） model developed earlier by the authors is used in this study. At first,a simulation study based on avalanche response time reveals that the upper cut-off frequency for DDR diamond IMPATTs is 1.5 THz, while the same for conventional DDR Si IMPATTs is much smaller, i.e. 0.5 THz. The L-S simulationresultsshowthattheDDRdiamondIMPATTdevicedeliversapeakRFpowerof7.79Wwithan18.17%conversion efficiency at 94 GHz; while at 1.5 THz, the peak power output and conversion efficiency decrease to6.19mWand8.17%respectively,taking50%voltagemodulation.AcomparativestudyofDDRIMPATTsbasedon diamond and Si shows that the former excels over the later as regards high frequency and high power performance at both mm-wave and THz frequency bands. The effect of band to band tunneling on the L-S properties of DDR diamond and Si IMPATTs has also been studied at different mm-wave and THz frequencies.     

一种包含热效应的InP DHBT大信号模型及其Verilog-A实现

A large signal model for InP/InGaAs double heterojunction bipolar transistors including thermal effects has been reported,which demonstrated good agreements of simulations with measurements.On the basis of the previous model in which the double heterojunction effect,current blocking effect and high current effect in current expression are considered,the effect of bandgap narrowing with temperature has been considered in transport current while a formula for model parameters as a function of temperature has been developed.This model is implemented by Verilog-A and embedded in ADS.The proposed model is verified with DC and large signal measurements.     

A 1-GHz Charge Pump PLL Frequency Synthesizer for IEEE 1394b PHY

The design procedure of an 1-GHz phase-locked loop (PLL)-based frequency synthesizer used in IEEE 1394b physical (PHY) system is presented in this paper. The PLL’s loop dynamics are analyzed in depth and theoretical relationships between all loop parameters are clearly described. All the parameters are derived and verified by Verilog-A model, which ensures the accuracy and efficiency of the circuit design and simulation. A 4-stage ring oscillator is employed to generate 1-GHz oscillation frequency and is divided into low frequency clocks by a feedback divider. The architecture is a third-order, type-2 charge pump PLL. The simulated settling time is less than 4μs. The RMS value of period jitter of the PLL’s output is 2.1 ps. The PLL core occupies an area of 0.12 mm2, one fourth of which is occupied by the MiM loop capacitors. The total current consumption of the chip is 16.5 mA. The chip has been sent for fabrication in 0.13 m complementary metal oxide semiconductor (CMOS) technology.     

Laser Driver for Optic Fiber Gyro with 4 mA to 200 mA Drive Current

Abstract---The stability of the drive current is very important for a laser driver, while it is difficult to maintain the current stable at a high value for the laser driver. On the other hand, the range of the drive current is expected to be as wide as possible to be applied to different kinds of lasers. In this paper, a high current laser driver for the superluminescent light emitting diode （SLED） is presented, which is used in the optic fiber gyro embedded by a 0.35 μm bipolar complementary metal-oxide-semiconductor transistor （BiCMOS） process. The laser driver provides automatic power control and certain value of current determined by the external resister. The system is based on the optic-electric feedback theory and uses the closed-loop control technique to maintain the drive current stable. The system is capable of producing stable current ranges from 4 mA to 200 mA when the value of external resister changes.     

The On-line Calibration Technology of System Delay Based on Dynamic Delay Cancellation for Generalized TT＆C Channel Simulator

An on-line system delay calibration method based on dynamic cancellation for generalized high-precision Tracking, telemetry and command （TT＆C） channel simulator is proposed. This method manages to estimate the time-varying system delay in real time through the coupling signal of input signal and simulated output signal, and then modifies the simulated parameters by the estimated value. With this method, it effectively avoids the effect of time-varying system delay caused by temperature drift, aging of components and other factors on high precision simulation. In this paper, the dynamic cancellation technology, which is the kernel and foundation of this method, is presented to eliminate the simulated motion law between the input signal and output signal. The time delay estimation method based on cross correlation and area barycenter arithmetic is introduced to estimate the time-varying system delay. The simulation results show the validity and high-precision performance.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

Optical vibration and deviation measurement of rotating machine parts

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer （LDV）.