应用于SC-UWB收发机的CMOS射频接收前端电路设计

设计了应用于单载波超宽带（SC-UWB）无线收发机中的CMOS射频接收前端电路. 该前端电路采用直接变频结构,包含一个差分低噪声放大器（LNA）、一个正交混频器和两个中频放大器。其中,LNA采用源级电感负反馈结构.首先给出了该类型LNA中输入匹配带宽关于栅源电容、工作频率及匹配目标值的表达式 然后考虑到栅极片上电感、键合电感及其精度,提出了在增益和功耗约束下的噪声因子优化策略。该LNA利用两级放大级的不同谐振点实现了7.1~8.1GHz频段上的平坦增益,并具有两种增益模式来改善接收机动态范围. 正交混频器采用折叠式双平衡吉尔伯特结构. 该射频前端电路采用TSMC0.18um RF CMOS工艺设计,芯片面积为1.43 mm2. 在高、低增益模式下,测得的最大转换增益分别为42dB和22dB,输入1dB压缩点为-40dBm和-20dBm,S11低于-18dB和-14.5dB,中频3dB带宽大于500MHz. 高增益模式下双边带噪声因子为4.7dB. 整个电路在1.8V供电电压下功耗为65mW。     

应用于TD-SCDMA/LTE/LTE-Advanced收发机的多频多模CMOS射频接收前端电路设计

设计了应用于TD-SCDMA/LTE/LTE-Advanced收发机中的多频段、多模式射频接收前端电路. 该前端电路采用直接变频结构,包含两个可调谐差分低噪声放大器、一个正交混频器和两个中频放大器。其中,两个独立的可调谐低噪声放大器覆盖了4个射频频段,在较低的功耗下实现足够的增益和噪声性能. 并且利用开关电容阵列来调节低噪声放大器的谐振频率点. 低噪声放大器通过混频器的驱动级跨导晶体管实现结合。正交混频器采用折叠式双平衡吉尔伯特结构,利用PMOS晶体管作为本振信号的开关对,从而降低1/f噪声. 前端电路具有3种增益模式以获得更大的动态范围. 模式配置和频段选择功能都由片上的SPI模块控制. 该射频前端电路采用TSMC0.18um RF CMOS工艺实现,芯片面积为1.3 mm2. 全部频段上测量的转换增益高于43dB,双边带噪声系数低于3.5dB. 整个电路在1.8V供电电压下,消耗电流约31mA。     

差分式低电压高增益电流模式集成射频接收机前端

本文提出了一种用于802.11 b 无线局域网的差分式低电压该增益电流模式射频前端集成电路。该电路包含一个差分式跨导低噪声放大器和一个差分式电流模式下混频器。单边跨导低噪声放大器仅含一个MOS晶体管和2个电感、2个电容构成。放大器中的栅-源并联电容Cx1 和 Cx2 不仅能减小栅-源寄生电容对谐振频率和输入匹配阻抗的的影响,而且能使得栅电感的取值变小。电流模式混频器由开关电流镜构成。调节开关电流镜晶体管之间沟道尺寸比值可以增加混频器的增益,从而增大射频接收机前端的功率增益。该射频前端电路工作在1V的电源电压下。使用chartered 0.18μm CMOS工艺进行了流片。 对芯片进行测试得到该射频前端的功率增益为17.48 dB, 输入三阶交调截点 (IIP3) 为 -7.02 dBm. 后仿真表示该芯片的噪声系数为4.5 dB,功耗仅为 14mW。     

用于便携式GPS接收机中的5.4mW低噪声高增益CMOS射频前端电路设计

设计了应用于便携式GPS接收机射频前端中的CMOS低噪声放大器和正交混频器. 该电路中的低噪声放大器采用带源端电感负反馈的输入级,并引入功耗约束下的噪声和输入同时匹配技术. 正交混频器基于吉尔伯特单元. 电路采用TSMC 0.18μm RF CMOS工艺实现,总的电压转换增益为35dB,级联噪声系数为2.4dB,输入1dB压缩点为-22dBm,输入匹配良好,输入回损为-22.3dB, 在1.8V电压供电下,整个全差分电路功耗为5.4mW.     

一种应用于GNSS接收机的无电感多模射频前端

本文设计了一种应用于GNSS接收机的无电感多模射频前端。与传统低噪声放大器结构不同,本设计使用了无电感电流模式以及利用噪声消除技术的低噪声放大器。其高阻输入的射频放大器进一步放大信号并将单端信号转为差分信号。后级无源混频器将信号下变频到中频并将信号传输到下一级的模拟电路模块。文中还有本振缓冲器实现压控振荡器的二分频和25%占空比的方波新号的产生用于控制混频器开关。测试结果表明该射频前端在1.2V电源电压下仅消耗6.7mA电流,并获得了良好的综合性能。射频前端的输入回损为-26dB,而1.43dB的低噪声系数也保证了良好的接收灵敏度。在射频前端电压增益为48dB情况下,测得的输入1dB压缩点为-43dBm。该电路采用了55nm标准CMOS工艺实现,面积非常小,仅仅为220 μm×280 μm左右。     

用于便携式GPS接收机中的5.4mW低噪声高增益CMOS射频前端电路设计

设计了应用于便携式GPS接收机射频前端中的CMOS低噪声放大器和正交混频器.该电路中的低噪声放大器采用带源端电感负反馈的输入级,并引入功耗约束下的噪声和输入同时匹配技术.正交混频器基于吉尔伯特单元.电路采用TSMC 0.18μm RFCMOS工艺实现,总的电压转换增益为35dB,级联噪声系数为2.4dB,输入ldB压缩点为-22dBm,输入匹配良好,输入回损为-22.3dB,在1.8V电压供电下,整个全差分电路功耗为5.4mW.     

CMOS蓝牙接收机前端的设计

采用TSMC 0.25μm CMOS工艺,设计了一个全集成2.4 GHz低中频蓝牙接收机前端,包括低噪声放大器(LNA)和混频器(Mixer)。LNA采用源极电感负反馈差分结构,混频器采用吉尔伯特(Gilbert)有源双平衡结构。在2.5 V工作电压下,整个接收机前端增益22.5 dB,噪声系数6.3 dB,三阶输入截止点-15.3 dBm,功耗38.4 mW。     

一种超外差低中频接收机射频前端的设计

介绍了一种应用于5.8GHz频段的专用短距离无线通信接收机前端,采用超外差低中频正交架构,通过合理规划接收机前端两次混频的频率可以有效解决镜像干扰和两条正交通路的失配。该前端包括低功耗的噪声抵消的低噪声放大器,其负载采用电容电感谐振电路,谐振频率可调,并具有一定的工艺稳定性。第一次混频采用电压模式无源混频器,第二次混频采用电流模式无源混频器。提出了一种简单有效的用于混频开关的偏置电路,射频混频开关采用反馈的方式确定偏置电压,中频混频开关的直流电压利用跨阻放大器的输出共模电压分压得到。芯片于TSMC 180nm工艺下流片,前端电路的有效面积为0.1mm2,整个链路的接收灵敏度达到-65dBm,接收数据率可以达到256kbps,在1.8V的工作电压下,消耗10.8mA的电流。     

基于CMOS工艺的一种低功耗高增益低噪声放大器

采用0.18μm CMOS工艺,两级共源结构实现了低功耗高增益的低噪声放大器设计。共源结构的级联采用电流共享技术,从而达到低功耗的目的。电路的输入端采用源极电感负反馈实现50Ω阻抗匹配,同时两级共源电路之间通过串联谐振相级联。该LNA工作在5.2 GHz,1.8 V电源电压,能提供20 dB的增益(S21为20 dB),而噪声系数为1.9 dB,输入匹配较好,S11为-32 dB。     

低功耗有源UHF-RFID标签芯片

采用SMIC 0.18 μm CMOS工艺,设计了一种低功耗的超高频有源RFID标签芯片射频接收前端电路.其中,低噪声放大器(LNA)采用共源共栅源极电感负反馈差分结构,下变频混频器(Mixer)采用吉尔伯特(Gilbert)有源双平衡结构.通过整体及模块电路优化,该电路在较低功耗下仍然具有较好性能.仿真结果表明,整个接收端功耗仅为14 mW,与传统射频前端芯片相比,功耗降低53%;整体增益为21.6 dB,噪声系数7.1 dB,三阶输入截止点-18.9 dBm,满足有源UHF-RFID标签芯片低功耗高性能的应用需求.     

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.     

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.     

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.     

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.