Analysis of substrate eddy effects and distribution effects in silicon-based inductor model

The concepts of substrate eddy influence factor and distribution-effects-occurring frequency are presented. The effects of substrate resistivity and inductor spiral length on the substrate eddy and distribution effects are captured. The substrate eddy influence factors of an inductor （6 turn, 3 060 μm in length） fabricated on low （ 1 Ω. cm） and high resistivity（ 1 000 Ω.cm） silicon substrates are 0. 3 and 0. 04, and the distribution-effects- occurring frequencies are 1.8 GHz and 14. 5 GHz, respectively. The measurement results show that the equivalent circuit model of the inductor on low resistivity silicon must take into consideration substrate eddy effects and distribution effects. However, the circuit model of the inductor on high resistivity silicon cannot take into account the substrate eddy effects and the distribution effects at the frequencies of interest. Its simple model shows agreement with the measurements, and the contrast is within 7%.

Silicon-based optoelectronic heterogeneous integration for optical interconnection

The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.

Constructing high-toughness polyimide binder with robust polarity and ion-conductive mechanisms ensuring long-term operational stability of silicon-based anodes

Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.

Regulating the Solvation Structure of Li^(+) Enables Chemical Prelithiation of Silicon-Based Anodes Toward High-Energy Lithium-Ion Batteries

The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.

Research Towards Terahertz Power Amplifiers in Silicon-Based Process

In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development of silicon-based THz PAs,mainly including silicon-based PAs with operating frequencies covering 100–300 GHz,are summarized in this paper.Particularly,we design an LC-balun-based two-stage differential cascode PA with a center frequency of 150 GHz and an output power of 14 dBm.Based on a Marchand balun,we report a 220 GHz three-stage differential cascode PA with a saturated output power of 9.5 dBm.To further increase the output power of THz PA,based on a four-way differential power combining technique,we report a 211–263 GHz dual-LC-tank-based broadband PA with a recorded 14.7 dBm Psat and 16.4 dB peak gain.All the above circuits are designed in a standard 130 nm silicon germanium(SiGe)BiCMOS process.

3D heterogeneous integration of wideband RF chips using silicon-based adapter board technology

An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapter board technology.Four layers of high-resistance silicon substrate stack packaging are implemented based on the wafer-level gold-gold bonding process.Each layer adopts though silicon via(TSV)technology to realize signal interconnection.A core monolithic integrated microwave chip(MMIC)is embedded in the silicon cavity,and the silicon-based filter is integrated with the high-resistance silicon substrate.The interconnect line,cavity and filter of the silicon-based adapter board are designed with AutoCAD,and HFSS is adopted for 3D electromagnetic field simulation.According to the measured results,the radio frequency(RF)of the mixing multi-function chip is 40-44 GHz and its intermediate frequency(IF)can cover the Ku band with a chip size of 10 mm×11 mm×1 mm.The multiplier multi-function chip operates at 16-20 GHz.The fundamental suppression is greater than 50 dB and the second harmonic suppression is better than 40 dB with a chip size of 8 mm×8 mm×1 mm.The cascaded fully assembled mixing component achieves a spur of better than-50 dBc and a gain of better than 15 dB.

Multifunctional silicon-based light emitting device in standard complementary metal oxide semiconductor technology

A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.

Micro-Mechanism of Silicon-Based Waveguide Surface Smoothing in Hydrogen Annealing

The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of silicon- hydrogen bonds on the surface migration movement of silicon atoms and the waveguide surface topography are revealed. The micro-migration from an upper state to a lower state of silicon atoms is driven by silicon- hydrogen bonding, which is the key to ameliorate the rough surface morphology of the silicon-based waveguide. The process of hydrogen annealing is experimentally validated based on the simulated parameters. The surface roughness declines from 1.523nm to 0.461 nm.

Modification of methyl oleate for silicon-based biological lubricating base oil

A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.

Design Technologies for Silicon-Based High-Efficiency RF Power Amplifiers:A Brief Overview

This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking （ET） design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.

Low insertion loss silicon-based spatial light modulator with high reflective materials outside Fabry–Perot cavity

The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.

High-performing silicon-based germanium Schottky photodetector with ITO transparent electrode

A near-infrared germanium(Ge)Schottky photodetector(PD)with an ultrathin silicon(Si)barrier enhancement layer between the indium-doped tin oxide(ITO)electrode and Ge epilayer on Si or silicon-on-insulator(SOI)is proposed and fabricated.The well-behaved ITO/Si cap/Ge Schottky junctions without intentional doping process for the Ge epilayer are formed on the Si and SOI substrates.The Si-and SOI-based ITO/Si cap/Ge Schottky PDs exhibit low dark current densities of 33 mA/cm2 and 44 mA/cm2,respectively.Benefited from the high transmissivity of ITO electrode and the reflectivity of SOI substrate,an optical responsivity of 0.19 A/W at 1550 nm wavelength is obtained for the SOI-based ITO/Si cap/Ge Schottky PD.These complementary metal–oxide–semiconductor(CMOS)compatible Si(or SOI)-based ITO/Si cap/Ge Schottky PDs are quite useful for detecting near-infrared wavelengths with high efficiency.

一种基于耦合电感的高增益软开关谐振变换器

该文提出了一种具有高增益、软开关的新型谐振变换器。该谐振变换器使用耦合电感来提高电压增益,升压比不仅取决于占空比,还取决于耦合电感的变比,具有高增益的优点。此外,由于采用了有源钳位技术,漏感中的能量可以被回收利用,用来对开关管的结电容充放电提供能量,从而实现软开关。由于采用了耦合电感,所提出的变换器可以在较低的开关管电压应力的情况下实现较高的输出电压,因此可以使用低导通电阻的低压器件,从而提升系统的效率。该文分析了该谐振变换器的工作原理,并推导了输出电压、关断电流应力等参数的解析表达式。在此基础上,从理论上分析了该变换器取得软开关的条件,并对该变换器的各个器件的电压电流应力进行分析,为器件选型提供了理论依据。最后,搭建1kW实验样机,针对该文提出的基于耦合电感的谐振变换器的高增益、软开关、低电压应力、高效率等性能进行了实验验证。通过实验得出所提出的拓扑可以在10倍增益的情况下达到最高97.5%的效率,表明所提拓扑的优越性。

一种应用于两相交错Boost的耦合电感的优化设计

两相交错Boost变换器具有纹波电流小的优势,但其采用的交错并联技术增加了电感数量,进而增加了装置的体积和重量,不利于其功率密度的提升。耦合电感通过将多个磁性元件集成到一个磁芯实现磁路的部分共享,从而减小了磁元件的数量和重量。因此,设计了一种反向耦合电感,并将其应用于两相交错Boost变换器,实现了装置功率密度的提升。首先,对反向耦合电感的工作原理和损耗来源进行分析;然后,在此基础上设计了一种改进的“EE”型磁芯,一方面有效提高了磁芯利用率,另一方面降低了电感的体积与重量;最后,通过有限元仿真对所提优化设计方案进行验证,同时搭建了功率等级为2 kW的两相交错Boost变换器实验平台。仿真和实验结果均验证了所提优化设计方案的有效性。

基于二次型升压变换器和开关电容的混合式升压方案研究

提出一种混合式高升压比DC-DC变换器。该变换器由二次型升压变换器、开关电容和耦合电感单元集成。为了减少元件的数量,耦合电感一次侧与二次型升压变换器共用;二次型升压变换器的输出电容一分为二,并与开关电容共用。由于电源和负载之间的共地特性,则输入电流连续。对所提变换器的电压增益进行了推导,并分析其电压应力。结果表明所提逆变器具备高电压增益、低电压应力的特性。最后,搭建了80 W的实验样机,实验结果验证了所提变换器的正确性和有效性。

一种应用于光伏的高增益DC/DC变换器研究

基于耦合电感、开关电容与输入电压源组成的基本功率单元,提出一种集成式新型DC/DC变换器。该拓扑结构具有模块化和可扩展性,耦合电感和开关电容结构组成的倍压单元提升了电路的升压比。漏感能量通过钳位电路回收,以降低开关管电压应力和功率损耗;同时缓解了二极管的反向恢复问题,优化了开关管和二极管的选择。详细介绍了稳态分析、工作原理和设计考虑;最后并制作了90 W实验样机,验证了理论分析的正确性。

基于寄生电感优化的分立器件布局方法研究

为了探究分立器件与PCB组合形成的半桥电路时采用何种布局方式才能尽最大限度减小线路寄生电感的问题,基于换流回路寄生电感概念,提出了一种经优化的分立器件在PCB上的布局方式,进而减小换流回路的寄生电感,随后通过有限元仿真软件评估并验证不同布局方式所产生的寄生电感,并结合LTspice电路仿真软件评估不同布局方式对器件电开关特性的影响,最后通过双脉冲实验验证了所设计的一种经过优化布局半桥电路的优越性.所提供的半桥电路的设计方法为分立器件在PCB上的布局提供了理论和技术支撑.

一种交叉倍压型高增益DC/DC变换器

针对光伏发电、燃料电池发电等领域对高增益直流变换器的需求,以两相交错并联升压变换器为研究对象,由2个含有电感的倍压单元组合设计出实现电压提升的交叉倍压结构,据此提出了一种新颖的交叉倍压型高增益DC/DC变换器。该变换器可实现(3n+4)/(1-d)倍的高电压增益(1∶n为耦合电感匝数比,d为变换器占空比),且具有电路器件的低电压应力特性。对于漏感引起的开关管电压尖峰问题,引入了钳位电容构成释放漏感能量通道,同时提升了输出电压。介绍了新型交叉倍压型高增益变换器的拓扑结构,分析了变换器各模态的工作过程,推导了电压增益、输入电流纹波及各器件电压应力等稳态特性,并搭建样机进行实验研究,验证了该直流变换技术方案的可行性和先进性。

高增益耦合电感组合Boost-Cuk变换器

为了解决传统变换器电压增益低的问题,将Boost变换器与Cuk变换器进行并联集成,并利用耦合电感倍压技术提高变换器的电压增益。设计而成的高增益耦合电感组合Boost-Cuk变换器保留了Cuk变换器输出电流的连续性,新型结构中使用无源钳位来吸收漏感能量,对寄生电容与漏感谐振引起的电压尖峰起到约束作用,降低了开关管的电压应力。描述了变换器电感电流连续模式(Continuous current mode,CCM)下的运行特点,并进行了该变换器的参数设计。最后,通过搭建一台100 W的试验样机来求证理论的正确性。

新型高增益耦合电感二次型变换器

将开关-耦合电感单元引入二次型变换器,采用一个耦合电感和两个独立电感,在开关管关断时,电感为电容充电;导通时,利用电容为负载供电。与传统变换器相比,所提出的变换器采用更少的器件,能得到高电压增益效果与低占空比。采用了降低电压应力的电容,二极管和半导体开关,开关管应力更低。提出了稳态和比较性能分析,制作了一台140W实验平台,给出实验数据与结论,验证了理论分析的正确性。