一种高电源抑制比低噪声快速启动的CMOS带隙基准电路设计

针对集成稳压器、射频电路等对精密电压基准的需求,本文设计了一款新型CMOS带隙基准电路.在降低高频噪声,增强输出对电源纹波抑制能力的同时引入快速启动电路,改善了RC滤波电路限制基准启动速度的问题.采用Hynix 0.5μmCMOS Hspice模型进行仿真后表明,此款带隙基准电路在较宽的频带范围内,噪声只有8.5μVrms,电源抑制比(PSRR)为100dB左右,启动时间在100μs以内.     

带有快速启动的高精密低噪声CMOS带隙基准

提出了一种新颖的带有快速启动的高精密、低噪声CMOS带隙基准电压源。RC滤波电路的引入降低了基准在高频处的噪声、增加了输出基准的电源抑制比,快速启动电路的引入改善了RC滤波电路限制基准启动速度的问题,并且为了使基准在电源上电的过程中能够正常的工作而增加了软启动电路。采用UMC 0.6μm 2P2M标准CMOS工艺进行设计和仿真,HSpice模拟表明基准具有较高的精度和较低的噪声,电源抑制比PSRR约为-80 dB。此外,由于快速启动电路的存在使得基准的建立时间从20 ms降至70μs。     

可快速启动的高PSRR低噪声CMOS带隙基准电压设计

集成电路的一个重要构成单元是电压基准，本文介绍了一种CMOS工艺下高精度带隙基准电路，它具有低噪声、高PSRR及快速启动的特点。在带隙基准输出端增加的RC滤波电路降低了高频噪声，增强了输出对输入纹波的抑制能力，并在此基础上引入快速启动电路，克服了RC滤波电路延缓基准启动速度的问题。在频率为100Hz至10MHz的范围内，噪声只有10．1μVms，PSRR为110dB左右，启动时间在70μs以内。     

一种无电阻高电源抑制比的CMOS带隙基准源

提出一种输出低于1V的、无电阻高电源抑制比的CMOS带隙基准源(BGR).该电路适用于片上电源转换器.用HJTC0.18μm CMOS工艺设计并流片实现了该带隙基准源,芯片面积(不包括pad和静电保护电路)为0.031mm2.测试结果表明,采用前调制器结构,带隙基准源电路的输出在100Hz与lkHz处分别获得了-70与-62dB的高电源抑制比.电路输出一个0.5582V的稳定参考电压,当温度在0～85℃范围内变化时,输出电压的变化仅为1.5mV.电源电压VDD在2.4～4V范围内变化时,带隙基准输出电压的变化不超过2mV.     

一种无电阻高电源抑制比的CMOS带隙基准源

提出一种输出低于1V的、无电阻高电源抑制比的CMOS带隙基准源(BGR).该电路适用于片上电源转换器.用HJTC0.18μm CMOS工艺设计并流片实现了该带隙基准源,芯片面积(不包括pad和静电保护电路)为0.031mm2.测试结果表明,采用前调制器结构,带隙基准源电路的输出在100Hz与lkHz处分别获得了-70与-62dB的高电源抑制比.电路输出一个0.5582V的稳定参考电压,当温度在0～85℃范围内变化时,输出电压的变化仅为1.5mV.电源电压VDD在2.4～4V范围内变化时,带隙基准输出电压的变化不超过2mV.     

一种带2阶温度补偿的负反馈箝位CMOS基准电压源

根据带隙基准电压源工作原理,设计了一种带2阶温度补偿的负反馈箝位CMOS基准电压源。不同于带放大电路的带隙基准电压源,该基准电压源不会受到失调的影响,采用的负反馈箝位技术使电路输出更稳定。加入了高阶补偿电路,改善了带隙基准电压源的温漂特性。电路输出阻抗的增大有效提高了电源抑制比。基于0.18 μm CMOS 工艺,采用Cadence Spectre软件对该电路进行了仿真,电源电压为2 V,在-40 ℃~110 ℃温度范围内温度系数为4.199 ×10-6/℃,输出基准电压为1.308 V,低频下电源抑制比为78.66 dB,功耗为120 μW,总输出噪声为0.12 mV/Hz。     

基于新型启动电路的高电源抑制带隙基准源

设计了一种基于新型启动电路的高电源抑制(PSR)的带隙基准电压源。启动电路可以在300ns的时间内使电路进入工作状态,同时可在10ns的时间内完全关断电路。可控的启动电路增加了电路使用的灵活性。本基准电路基于新加坡Chartered0.25μmN阱CMOS工艺实现,已应用于射频调谐器当中。测试结果表明,基准电压源在低频段的电源抑制PSR≈123dB,高频段PSR>50dB,电路采用一阶温度补偿技术,在0～100℃的温度范围内输出基准电压的温度系数(TC)约为12ppm/℃。     

一种新型无运放CMOS带隙基准电路

介绍了带隙基准原理和常规的带隙基准电路,设计了一种新型无运放带隙基准电路。该电路利用MOS电流镜和负反馈箝位技术,避免了运放的使用,从而消除了运放带隙基准电路中运放的失调电压和电源抑制比等对基准源精度的影响。该新型电路比传统无运放带隙基准电路具有更高的精度和电源抑制比。基于0.18μm标准CMOS工艺,在Cadence Spectre环境下仿真。采用2.5V电源电压,在-40℃～125℃温度范围的温度系数为6.73×10-6/℃,电源抑制比为54.8dB,功耗仅有0.25mW。     

一种高电源抑制比曲率补偿带隙基准电压源

在对传统典型CMOS带隙电压基准源电路分析基础上提出了一种高精度、高电源抑制带隙电压基准源。采用二阶曲率补偿技术,电路采用预电压调整电路,为基准电路提供稳定的电源,提高了电源抑制比,在提高精度的同时兼顾了电源抑制比,整个电路采用了CSMC0.5μm标准CMOS工艺实现,采用spectre进行进行仿真,仿真结果显示当温度为-40℃~80℃,输出基准电压变化小于1mV,温度系数为3.29×10-6℃,低频时(1kHz)的电源抑制比达到75dB,基准电路在高于3.3V电源电压下可以稳定工作,具有较好的性能。     

一种10-ppm/~oC低压CMOS带隙电压基准源设计

在对传统CMOS带隙电压基准源电路分析和总结的基础上,综合一级温度补偿、电流反馈和电阻二次分压技术,提出了一种10-ppm/oC低压CMOS带隙电压基准源。采用差分放大器作为基准源的负反馈运放,简化了电路的设计,放大器的输出用于产生自身的电流源偏置,提高了电源抑制比(PSRR)。整个电路采用TSMC 0.35mm CMOS工艺实现,采用Hspice进行仿真,仿真结果证明了基准源具有低温度系数和高电源抑制比。     

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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