一种具有温度补偿的时钟振荡器设计

介绍了一种采用0.35μm CMOS工艺制作的具有温度补偿的时钟振荡器电路。从环形振荡器的基本原理出发,基于对CMOS工艺各种非理想性因素的分析,提出一种新型的工艺补偿电路,减小振荡器偏置电流随阈值电压的漂移;在延迟单元的设计中,引入NMOS交叉耦合对组成的交流负阻抗来进一步补偿PMOS迁移率随温度的变化,从而有效抑制输出频率随温度的变化。该振荡器电路用于MEMS加速度计读出电路芯片。样品电路测试结果表明,在-20~100℃温度范围内,时钟振荡器的频率仅变化38kHz。     

集成CMOS环形振荡器频漂补偿的实现

为了提高CMOS环形振荡器的稳定度,以温度传感器作为检测电路,利用单稳态电路整形、滤波,把频率变化转变为电压变化对压控振荡器(VCO)进行负反馈调节,在温度变化和电源微小波动时,抑制了频率漂移.测试结果表明:CMOS环形振荡器输出频率为3.55 GHz,在温度区间-20～80℃内最差稳定度为2.45％,优于2.5％,达...     

一种阈值自调整的高速串行信号丢失检测电路

设计了一种应用于高速串行接收端的阈值自调整信号丢失检测电路,其阈值电压可跟随输入信号的共模电平波动和输入数据率的改变来进行自调整,因此可增大输入信号共模范围,适应更多的信号传输速率。该电路基于SMIC 0.13 μm标准CMOS工艺实现,版图尺寸为269 μm×118 μm。仿真结果表明,该电路能够正确检测共模电平在1.15~1.90 V范围内、差模摆幅大于150 mV的串行差分信号。     

一种具有快速锁定特性的自适应锁相环设计

基于传统电荷泵锁相环(CP-PLL)系统结构设计了一个具有快速锁定特性,环路带宽自适应调节的锁相环。对其中的电荷泵(CP)、低通滤波器(LPF)和环形振荡器(VCO)子模块电路采用了新颖的设计,用UMC 0.18μMix-mode CMOS工艺实现了电路,仿真结果表明系统有较高的性能,适用于USB2.0等高速串行数据传输系统。     

一种基于电流舵逻辑的环形振荡器

文章分析了电流舵逻辑门的动/静态特性.为了比较电流舵环形振荡器和普通数字反相器环形振荡器,采用1.2 μm标准CMOS工艺,设计并制作了两种环形振荡器.仿真和试验结果表明,电流舵环形振荡器具有低噪声和频率不随电压变化的特点,但其功耗比较大,适合于噪声要求高而功耗要求不高的电路.     

5 GHz 0.18 μm CMOS工艺正交输出VCO

文章采用全开关状态的延时单元和双延时路径两种电路技术设计了一种高工作频率、低相位噪声的环形振荡器.环路级数采用偶数级来获得两路相位相差90 ℃的正交输出时钟.采用TSMC 0.18 μm CMOS工艺进行流片,电压控制振荡器(VCO)的频率范围为4.9～5.5 GHz,模拟的相位噪声为-119.3 dBc/Hz@5 M,采用1.8 V电源电压,核芯电路的功耗为30 mW, 振荡器核芯面积为60 μm×60 μm.     

偶数级差分环形振荡器的稳定平衡态分析

与具有奇数增益级的差分环形振荡器不同,偶数级振荡器除了具有能够起振的非稳定平衡态,还有可能在起振前处于一种稳定平衡状态从而使电路锁定不能起振。该文主要分析了这种稳定平衡状态存在的原理,同时为了避免振荡器设计中的这种风险,提出了一种振荡器起振电路,使得电路在起振前处于接近非稳定平衡态的状态,从而能够快速起振。在0.13 m 1P8M 标准CMOS工艺下流片实现的4级差分环形压控振荡器(VCO)及其改进版本很好地验证了该文提出的理论和解决方法。经测试发现,第1款不带起振电路的4级VCO芯片锁定于稳定平衡态,不能起振;两种改进版本3级VCO和带起振电路的4级VCO都能够正常输出振荡信号。     

SOI CMOS器件研究

利用0.35μm工艺条件实现了性能优良的小尺寸全耗尽的器件硅绝缘体技术(SOI)互补金属氧化物半导体(FD SOI CMOS)器件,器件制作采用双多晶硅栅工艺、低掺杂浓度源/漏(LDD)结构以及突起的源漏区。这种结构的器件防止漏的击穿,减小短沟道效应(SCE)和漏感应势垒降低效应(DIBL);突起的源漏区增加了源漏区的厚度并减小源漏区的串联电阻,增强了器件的电流驱动能力。设计了101级环形振荡器电路,并对该电路进行测试与分析。根据在3V工作电压下环形振荡器电路的振荡波形图,计算出其单级门延迟时间为45ps,远小于体硅CMOS的单级门延迟时间。     

基于90 nm工艺节点的MOSFET版图失配研究

研究了CMOS模拟集成电路的不同版图结构对电路性能的影响规律,探讨了不同版图结构对工艺波动的抑制作用.通过采用90 nm CMOS工艺设计了8种不同宽长比(W/L)的数模转换器(DAC),分别利用单栅与多指栅结构实现该DAC电流源输出驱动管阵列,并将其作为研究对象进行了分析.通过分析金属氧化物半导体场效应晶体管(MOSFET)阈值电压VTH和DAC输出电压Vout的实测数据,对CMOS模拟集成电路的最优版图设计方案进行了探讨.最后,利用本研究结果设计了一款90 nm工艺的低功耗CMOS运算放大器,相比传统版图结构,该放大器的工艺波动抑制能力提高了5.87％.     

一种高频二级交叉耦合压控振荡器

采用等效为电感特性的负载和交叉耦合结构两种电路技术设计了一种高工作频率、低相位噪声的二级环形振荡器(two-stage VCO).因为是偶数级的环路级数,振荡器可输出两路相差90度的正交输出时钟.采用TSMC0.25μm CMOS工艺参数,用Cadence的spectre软件进行仿真,在2.5V电压下,工作频率为5GHz时,偏离主频1MHz处相位噪声为-87dBc/Hz.功耗:16.7mW.     

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.     

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.     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its