一种高性能全差分双环路VCO的设计

设计了一种基于SMIC 0.18μm RF 1P6MCMOS工艺的高性能全差分环形压控振荡器(ring-VCO),采用双环连接方式,并运用交叉耦合正反馈来提高性能。在1.8V电源电压下对电路进行仿真,结果表明:1)中心频率为500MHz的环形VCO频率调谐范围为341～658MHz,增益最大值Kvco为-278.8MHz/V,谐振在500MHz下VCO的相位噪声为-104dBc/Hz@1MHz,功耗为22mW;2)中心频率为2.5GHz的环形VCO频率调谐范围为2.27～2.79GHz,增益最大值Kvco为-514.6MHz/V,谐振在2.5GHz下VCO的相位噪声为-98dBc/Hz@1MHz,功耗为32mW。该VCO适用于低压电路、高精度锁相环等。     

一种低压低功耗伪差分环形压控振荡器的设计

基于TSMC 28 nm CMOS工艺设计了一个伪差分结构的低压低功耗CMOS环形振荡器。电路包括偏置电路、环形振荡器和输出缓冲器。伪差分环形振荡器有五级延迟单元,延迟单元采用Maneatis对称负载。在Cadence Spectre上进行前仿真。结果表明,VCO工作在0.9 V电源电压下时,其频率调谐范围为0.65 GHz~4.12 GHz。在3.6 GHz以下频率范围内具有很好的调谐线性度。中心频率约为2.3 GHz时,其相位噪声为-79.06 dBc/Hz@1 MHz。输出缓冲电路能够实现轨对轨的输出摆幅,输出占空比可优化至50%。环形振荡器的功耗约为5.7 mW。     

一种低功耗环形振荡器的噪声分析与设计

介绍了一种采用CSMC 0.153 μm CMOS工艺制作的差分环形振荡器。分析了环形振荡器延时单元的选取和设计原理,以及输入差分对管跨导和负载电阻对环振相位噪声的贡献,得到负载为线性区偏置MOS管时低功耗低相位噪声环振的设计方法。在相位噪声变化较小时,采用电容阵列结构拓宽了环形振荡器频率的调谐范围。测试结果表明,该环形振荡器输出频率范围为513 MHz ~1.8 GHz;在振荡频率为1.57 GHz频偏1 MHz处,相位噪声为-84.11 dBc/Hz,功耗为3.88 mW。     

一种低调谐增益变化的宽带电感电容压控振荡器

设计了一个应用于数字电视调谐器的宽带电感电容压控振荡器.该振荡器包含了一个开关可变电容阵列,用以抑制调谐增益的变化.整个电路采用0.18μm CMOS工艺实现.测试结果表明:压控振荡器的频率范围从1.17GHz至2.03GHz(53.8%);调谐增益从69MHz/V变化至93MHz/V,其变化幅度与最大值相比为25.8%;最差相位噪声为-126dBc/Hz@1MHz;在1.5V电源电压下,压控振荡器的功耗约为9mW.     

一种低调谐增益变化的宽带电感电容压控振荡器

设计了一个应用于数字电视调谐器的宽带电感电容压控振荡器.该振荡器包含了一个开关可变电容阵列,用以抑制调谐增益的变化.整个电路采用0.18μm CMOS工艺实现.测试结果表明:压控振荡器的频率范围从1.17GHz至2.03GHz(53.8%);调谐增益从69MHz/V变化至93MHz/V,其变化幅度与最大值相比为25.8%;最差相位噪声为-126dBc/Hz@1MHz;在1.5V电源电压下,压控振荡器的功耗约为9mW.     

一种低功耗宽频率调谐范围的伪差分环形VCO

设计了一种低功耗、宽频率调谐范围的伪差分环形压控振荡器(VCO).电路设计分为振荡环路设计和电流源设计两部分.在振荡器的振荡环路部分,提出了一种新颖的降低功耗的方法,即通过动态地调节接入振荡环路的锁存器,减小驱动电流,降低功耗;在振荡器的控制电源部分,采用gain-boost结构,设计了一款理想的可控双电流源,实现了振荡器的宽频率调谐范围.基于SMIC 65 nm工艺,在1.8V工作电压下,对振荡器进行了后仿验证.结果表明,在频率为900 MHz时,振荡器的功耗仅为3.564 mW;当控制电压在0.6～1.8 V变化时,振荡器的频率调谐范围可宽达0.495 ～1.499 GHz.     

一种全差分双路延迟环形VCO的设计

采用SMIC 40 nm CMOS工艺,设计了一款采用双路延迟结构和新型延迟单元的高性能全差分环形压控振荡器。仿真结果表明,该VCO电路可实现高振荡频率和宽调谐电压,调节频率范围为5.5~8 GHz,控制电压调节范围为0~VDD。谐振频率为6.25 GHz时,消耗功耗为4.4 mW,相位噪声为-85 dBc@1 MHz。该VCO可应用于高速IO时钟恢复及频率发生器电路中。     

基于GaAs工艺的36GHz压控振荡器

利用法国OMMIC公司的0.2μm GaAs PHEMT工艺,设计实现了一个36GHz压控振荡器电路.该电路采用完全差分的调谐振荡器结构,通过引进容性源极耦合差动电流放大器和调谐负载电路,提高了电路的性能.测试表明:该压控振荡器中心频率为36GHz,调谐范围约为800MHz,在偏离中心频率10MHz处的单边带相位噪声为-98.83dBc/Hz.芯片面积为0.5mm×1mm,采用-5V单电源供电,核心单元功耗约为200mW.     

基于GaAs工艺的36GHz压控振荡器

利用法国OMMIC公司的0.2μm GaAs PHEMT工艺,设计实现了一个36GHz压控振荡器电路.该电路采用完全差分的调谐振荡器结构,通过引进容性源极耦合差动电流放大器和调谐负载电路,提高了电路的性能.测试表明:该压控振荡器中心频率为36GHz,调谐范围约为800MHz,在偏离中心频率10MHz处的单边带相位噪声为-98.83dBc/Hz.芯片面积为0.5mm×1mm,采用-5V单电源供电,核心单元功耗约为200mW.     

一种基于注入锁定环形振荡器的时钟产生电路

提出了一种基于谐波注入锁定数控环形振荡器的时钟产生电路。采用注入锁定技术,极大地抑制了环形振荡器的相位噪声。在频率调谐环路关断的情况下,数控式振荡器可以正常工作,与需要一直工作的锁相环相比,大大节省了功耗。分析了电路的参考杂散性能。在65 nm CMOS工艺下进行流片测试,芯片的面积约为0.2 mm²。测试结果表明,设计的时钟产生电路工作在600 MHz时,1 MHz频偏处的相位噪声为-132 dBc/Hz,在1 V的电源电压下仅消耗了5 mA的电流。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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 rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.