双层螺旋RF MEMS电感的模拟与设计

分析了双层螺旋电感的等效电路模型,研究了一种与传统CMOS工艺兼容的MEMS工艺,通过腐蚀电感结构下的硅衬底使电感悬空.利用HFSS软件对一些双层螺旋微电感进行了模拟,模拟结果表明,相比传统单层电感,双层电感可以减少60%的芯片面积,10nH的电感也只需要很小的面积,经过MEMS后处理的双层螺旋电感的最大Q值都超过了20.     

硅衬底RF集成电路中螺旋电感的建模和分析

对硅衬底RF集成电路中的螺旋电感进行电磁场建模,考虑了衬底损耗效应,并通过电路分析和网络分析技术得到了二端口简化电感模型.该模型在特定的截止频率以下可提供可靠的电路系统仿真.利用该模型分析了硅衬底的损耗对螺旋电感品质因素(Q)的影响.     

Design, Optimization of RF Spiral Inductors Using Scalable Compact and Accurate Models

This paper presents a practical and structured approach to the design and optimization of RF spiral inductors. The accuracy of proposed modified accurate distributed and scalable compact lumped models are quantitatively compared with experimental results. Based on the new scalable compact lumped model, a quality factor optimization engine is verified. The inductors under study include single/double layer inductors, metallization shunted as well as octagonal shaped inductors. Experimental results suggest that the new modified accurate distributed model is more accurate than existing models for predicting spiral inductor performance to even beyond resonance frequencies. In addition, using a self developed optimization engine, the new scalable compact model is sufficiently accurate in determining the optimum inductor geometry. Consequently, a web-based program (SISOP) is developed to provide RF designers total solution to spiral inductor design, optimization and integration of spiral inductor model into their lump circuit simulators.     

RF inductors with suspended and copper coated thick crystalline silicon spirals for monolithic MEMS LC circuits

This letter presents a novel radio frequency (RF) inductor in a monolithic inductor-capacitor circuit developed by using micro-electromechanical systems (MEMS) fabrication technology. The inductor consists of 40-/spl mu/m-thick single crystalline silicon spiral with copper surface coating as the conductor, which is suspended on a glass substrate. The fabricated inductor exhibits a self-resonance frequency higher than 15GHz, with the quality factor more than 35 and inductance over 5nH at 11.3GHz. Simulations based on a compact equivalent circuit model with parameters extracted using a characteristic-function approach have also been carried out for the inductor, and good agreement with measurements is obtained.     

表面镀铜悬浮厚单晶硅螺线MEMS电感

报道了一种由悬浮在玻璃衬底上的表面镀铜平面单晶硅螺线构成的新型MEMS电感,可消除衬底损耗及减小电阻损耗.采用一种硅玻璃键合-深刻蚀成型释放工艺并结合无电镀技术制作该电感,形成厚约40μm的硅螺线,在硅螺线表面镀有高保形厚铜镀层,在铜镀层表面镀有起钝化保护作用的薄镍镀层.该电感的自谐振频率超过15GHz,在11.3GHz下,品质因子达到约40,电感值超过5nH.基于该电感的简化等效电路模型,采用一种特征函数法进行了参数提取,模拟结果与测量结果符合得很好.     

Temperature behavior of spiral inductors on high resistivity substrate in SOI CMOS technology

This paper reviews and analyzes a compact model for integrated planar spiral inductors on standard and high resistivity substrates in silicon-on-insulator (SOI) technology. The inductors have been characterized over a temperature range from 25 to 200 °C. The temperature variation of each model parameter has been investigated. It demonstrates that only the variations of the metallic losses versus temperature have to be taken into account to model properly the high frequency behavior over a wide temperature range of a spiral inductor integrated on silicon high resistivity substrate. Based on these experimental and characterization results, guidelines for practical inductor designs in RFICs for high-temperature applications are drawn.     

Physical modeling of spiral inductors on silicon

This paper presents a physical model for planar spiral inductors on silicon, which accounts for eddy current effect in the conductor, crossover capacitance between the spiral and center-tap, capacitance between the spiral and substrate, substrate ohmic loss, and substrate capacitance. The model has been confirmed with measured results of inductors having a wide range of layout and process parameters. This scalable inductor model enables the prediction and optimization of inductor performance     

30-100-GHz inductors and transformers for millimeter-wave (Bi)CMOS integrated circuits

Silicon planar and three-dimensional inductors and transformers were designed and characterized on-wafer up to 100 GHz. Self-resonance frequencies (SRFs) beyond 100 GHz were obtained, demonstrating for the first time that spiral structures are suitable for applications such as 60-GHz wireless local area network and 77-GHz automotive RADAR. Minimizing area over substrate is critical to achieving high SRF. A stacked transformer is reported with S/sub 21/ of -2.5 dB at 50 GHz, and which offers improved performance and less area (30 /spl mu/m/spl times/30 /spl mu/m) than planar transformers or microstrip couplers. A compact inductor model is described, along with a methodology for extracting model parameters from simulated or measured y-parameters. Millimeter-wave SiGe BiCMOS mixer and voltage-controlled-oscillator circuits employing spiral inductors are presented with better or comparable performance to previously reported transmission-line-based circuits.     

Micromachined high-Q inductors in a 0.18-μm copper interconnectlow-k dielectric CMOS process

On-chip spiral micromachined inductors fabricated in a 0.18-μm digital CMOS process with 6-level copper interconnect and low-K dielectric are described. A post-CMOS maskless micromachining process compatible with the CMOS materials and design rules has been developed to create inductors suspended above the substrate with the inter-turn dielectric removed. Such inductors have higher quality factors as substrate losses are eliminated by silicon removal and increased self-resonant frequency due to reduction of inter-turn and substrate parasitic capacitances. Quality factors up to 12 were obtained for a 3.2-nH micromachined inductor at 7.5 GHz. Improvements of up to 180% in maximum quality factor, along with 40%-70% increase in self-resonant frequency were seen over conventional inductors. The effects of micromachining on inductor performance was modeled using a physics-based model with predictive capability. The model was verified by measurements at various stages of the post-CMOS processing. Micromachined inductor quality factor is limited by series resistance up to a predicted metal thickness of between 6-10 μm     

Equivalent circuit for broadband modelling of on-chip spiral inductors up to millimetre-wave frequencies

A single-stage expandable equivalent circuit is proposed to model an on-chip spiral inductor up to several times its first self-resonant frequency. The equivalent circuit adopts a modified T-section network configuration to achieve an extremely large bandwidth. The modelled results for a series of round spiral inductors fabricated with different turn numbers on InGaAs substrate demonstrate good agreement with measured results over a measurement frequency range up to 50 GHz.     

A broadband and scalable model for on-chip inductors incorporating substrate and conductor loss effects

A new T-model has been developed to accurately simulate the broadband characteristics of on-Si-chip spiral inductors, up to 20 GHz. The spiral coil and substrate RLC networks built in the model play a key role responsible for conductor loss and substrate loss in the wideband regime, which cannot be accurately described by the conventional /spl pi/-model. Good match with the measured S-parameters, L(/spl omega/), Re(Z/sub in/(/spl omega/)), and Q(/spl omega/) proves the proposed T-model. Besides the broadband feature, scalability has been justified by good match with a linear function of coil numbers for all model parameters employed in the RLC networks. The satisfactory scalability manifest themselves physical parameters rather than curve fitting. A parameter extraction flow is established through equivalent circuit analysis to enable automatic parameter extraction and optimization. This scalable inductor model will facilitate optimization design of on-chip inductor and the accuracy proven up to 20 GHz can improve RF circuit simulation accuracy demanded by broadband design.     

硅基平面螺旋电感的等效电路模型和参数提取

针对螺旋电感传统等效电路模型的不足,提出了一种改进形式的集总参数等效电路模型.该等效电路模型能很好地反映出电感参数随频率变化的实际效应,可适用于从低频到自谐振频率的宽频带范围.同时,应用电磁场全波分析方法对CMOS工艺下平面螺旋电感进行仿真分析.从得到的散射参数中提取电感L、Q值及自谐振频率.基于参数优化和曲线拟合技术,给出了等效电路模型中各个元件值的多变量闭合表达式.这些表达式可方便地用于集成电路的设计和优化,从而提高电路设计的性能和效率.     

Parameters extraction and modeling for planar spiral inductor on Si-SiO/sub 2/ substrates by DDM for conformal modules

In this paper, the domain decomposition method (DDM) for conformal modules is used to get simple analytic expressions for parameters of planar spiral inductors on Si-SiO/sub 2/ substrates. The conductor and substrate losses are considered in the expressions. The quality factor of the spiral inductor is computed with a transmission-line mode and compared with previously published experimental results, showing that DDM model is accurate and efficient for modeling an on-chip spiral inductor on Si-SiO/sub 2/ substrates.     

On-chip spiral inductors with patterned ground shields for Si-basedRF ICs

This paper presents a patterned ground shield inserted between an on-chip spiral inductor and silicon substrate. The patterned ground shield can be realized in standard silicon technologies without additional processing steps. The impacts of shield resistance and pattern on inductance, parasitic resistances and capacitances, and quality factor are studied extensively. Experimental results show that a polysilicon patterned ground shield achieves the most improvement. At 1-2 GHz, the addition of the shield increases the inductor quality factor up to 33% and reduces the substrate coupling between two adjacent inductors by as much as 25 dB. We also demonstrate that the quality factor of a 2-GHz LC tank can be nearly doubled with a shielded inductor     

Large Q-factor improvement for spiral inductors on silicon using proton implantation

We have improved the Q-factor of a 4.6 nH spiral inductor, fabricated on a standard Si substrate, by more than 60%, by using an optimized proton implantation process. The inductor was fabricated in a 1-poly-6-metal process, and implanted after processing. The implantation increased the substrate impedance by /spl sim/ one order of magnitude without disturbing the inductor value before resonance. The S-parameters were well described by an equivalent circuit model. The significantly improved inductor performance and VLSI-compatible process makes the proton implantation suitable for high performance RF ICs.     

新颖的衬底pn结隔离型硅射频集成电感

提出了一种新的减小硅集成电感衬底损耗的方法 .这种方法是直接在硅衬底形成间隔的 pn结隔离以阻止螺旋电感诱导的涡流 .衬底 pn结间隔能用标准硅工艺实现而不需另外的工艺 .本文设计和制作了硅集成电路 ,测量了硅集成电感的 S参数并且从测量数据提取了电感的参数 .研究了衬底结隔离对硅集成电感的品质因素 Q的影响 .结果表明一定深度的衬底结隔离能够取得很好的效果 .在 3GHz,衬底 pn结隔离能使电感的品质因素 Q值提高4 0 % .     

基于柔性衬底的平面螺旋电感的计算与仿真

提出了一种基于柔性衬底的平面螺旋电感,介绍了柔性衬底的优点,对比了平面电感的结构类型,给出了平面螺旋电感的自感、电容、串联电阻及互感的计算方法,并对方形平面电感进行了仿真.     

On the design of RF spiral inductors on silicon

This review of design principles for implementation of a spiral inductor in a silicon integrated circuit fabrication process summarizes prior art in this field. In addition, a fast and physics-based inductor model is exploited to put the results contributed by many different groups in various technologies and achieved over the past eight years into perspective. Inductors are compared not only by their maximum quality factors (Q/sub max/), but also by taking the frequency at Q/sub max/, the inductance value (L), the self-resonance frequency (f/sub SR/), and the coil area into account. It is further explained that the spiral coil structure on a lossy silicon substrate can operate in three different modes, depending at first order on the silicon doping concentration. Ranging from high to low substrate resistivity, inductor-mode, resonator-mode, and eddy-current regimes are defined by characteristic changes of Q/sub max/, L, and f/sub SR/. The advantages and disadvantages of patterned or blanket resistive ground shields between the inductor coil and substrate and the effect of a substrate contact on the inductor are also addressed in this paper. Exploring optimum inductor designs under various constraints leverages the speed of the model. Finally, in view of the continuously increasing operating frequencies in advancing to new generations of RF systems, the range of feasible inductance values for given quality factors are predicted on the basis of optimum technological features.     

A new wideband compact model for spiral inductors in RFICs

A new wide-band compact model for planar spiral inductors on lossy silicon substrate is presented. Transformer loops are used in the series branch of the equivalent circuit model to include the effects of the frequency-dependent losses, in particular eddy-current loss in the silicon substrate. The new compact model and the standard 9-element model are extracted from measurement data of a typical 1.5-nH spiral fabricated on a low-resistivity CMOS substrate over a frequency range of 0.1 to 10 GHz. The frequency-dependent series resistance and inductance as well as the quality factor obtained with the new model are in excellent agreement with the measured results     

基于改进1-π拓扑结构的螺旋电感可扩展模型

随着射频集成电路空前发展,电感作为射频电路中重要无源器件应用越来越广.目前其仿真模型应用频率范围较窄并且仿真结果与测试结果拟合较差.本文提出了基于0.13μm SOI CMOS工艺的片上螺旋电感修改模型.模型采用了1-π等效电路,包含有表征衬底涡流的RL并联网络并且改进了由趋肤效应引起的金属线圈中涡流的表征.利用数理统计中的回归分析方法,得到扩展模型参数的表达式.制备了13种不同尺寸的片上螺旋电感用于验证模型.本文提出的方法,对不同尺寸的电感在频率达到自谐振频率以上的行为提供了更好的电路解释.