A very high Q-factor inductor using MEMS technology

Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2010, 2010

This paper presents the design and optimisation of a very high Quality (Q) factor inductor using MEM8 technology for lOGHz to 20GHz frequency band. The effects of various parameters of a symmetric inductor structure on the Q-factor and inductance are thoroughly analysed. The inductor has been designed on Sillcon-on-Sapphire (808) substrate because it offers superior characteristics of low substrate loss due to the high resistivity of the sapphire material and low capacitive coupling to the substrate. It is also been suspended from the substrate in order to reduce the substrate loss and improved the Q factor. Results indicate that a maximum Q factor of 192 for a l.13nH inductance at 12GHz is achieved after optimising the symmetric inductor. I.

Journal of Microelectromechanical Systems, 2017

Inductors are primary elements in many radio frequency circuitries and devices. This review gives a comprehensive survey on the developments and performances of fixed and variable RF MEMS inductors. MEMS inductors are the core of this review due to their high-yield performances and the wide choices of possible tuning techniques. First, the factors that constrain high-performance micro coils and the conventional solutions to overcome them are highlighted. Next, this paper systematically reviews varieties of MEMS inductors starting with the fixed inductors and according to inductors' topologies and performance enhancement techniques. In addition, the variable types of inductors are subsequently discussed, mainly from the point of view of their tuning techniques. Many quantitative comparisons are given in terms of the values of quality factor, inductance, self-resonance frequency, and tuning range. This will provide readers with an overall evaluation of different studies and assist them in choosing the inductors' topologies and layouts that best suit their applications. This review also sheds light on different and most common RF MEMS inductors applications, including RF communication devices and wireless sensors and actuators applications. Finally, this paper summarizes the best fabrication and tuning approaches inferred from the reviewed works and discusses some design guidelines to achieve better inductor performance. [2016-0125] Index Terms-Micro coils, microelectromechanical system (MEMS), variable inductors, 3D inductors, quality factor. I. INTRODUCTION I NDUCTORS are elementary and essential electrical elements that are constructed from wire loops or coils. Without them, many radio frequency (RF) devices such as transceivers, voltage-controlled oscillators (VCOs), low-noise amplifiers (LNAs), matching networks, and filters, could not be realized. Spiral-type inductors on silicon have begun to receive more attentions due to their suitability for mass production using the standard complementary metal oxide semiconductors (CMOS) manufacturing technology [1].

1998

High Q-factor inductors on silicon are an essential component, for RF circuit designers to meet increasing consumer desires for low cost, small size, and long battery life in wireless systems. In this thesis we have developed a simple scalable lumped element circuit model for aluminum-copper metallization integrated inductors, that is accurate to within 20% for frequencies up to the self-resonant frequency. Using this model, we have developed a simulator that is suitable for inductor design. Our simulator suggests that inductors with Qfactors of 3 10.9 in the frequency range of 1 GHz 2.4 GHz, for inductances of 2 nH 12 nH should be feasible using existing RF processing technology. These inductors have selfresonant frequencies above 10 GHz and areas of at most 1.6x10 5 gm2 . Thesis Supervisor: Brad W. Scharf Title: Division Fellow, Analog Devices Inc. Thesis Supervisor: Jesus A. del Alamo Title: Associate Professor of Electrical Engineering and Computer Science, M.I.T. Acknowledgment...

2010 Fifth IEEE International Symposium on Electronic Design, Test & Applications, 2010

This paper presents the design and optimisation of high quality (Q) factor inductors using Micro/Nano Electro-Mechanical Systems (NEMS/MEMS) technology for 10GHz to 20GHz frequency band. Three inductors have been designed with rectangular, circular and symmetric topologies. Comparison has been made amongst the three to determine the best Q-factor. Inductors are designed on Silicon-on-Sapphire (SOS) because of its advantages including high resistivity and low parasitic capacitance. The effects of various parameters such as outer diameter (OD), the width of metal traces (W), the thickness of the metal (T) and the air gap (AG) on the Q-factor and inductance performances are thoroughly investigated. Results indicate that the symmetric inductor has highest Qfactor with peak Q of 192 at 12GHz for a 1.13nH.

Sensors & Transducers, 2010

Wireless biosensor networks (WBSNs) collect information about biological responses and process it using scattered battery-power sensor nodes. Such nodes demand ultra low-power consumption for longer operating time. Ultra Wide Band (UWB) is a potential solution for WBSNs due to its advantage in low power consumption at reasonable data rate. However, such UBW technology requires high quality (Q) factor passive components. This paper presents detailed analysis, design and optimization of physical parameters of silicon-on-sapphire (SOS) and micro-electro-mechanical-systems (MEMS) inductors for application in UWB transceivers. Results showed that the 1.5 nH SOS inductor achieved Q factor of 111 and MEMS inductor achieved Q factor of 45 at 4 GHz frequency. The voltage controlled oscillator (VCO) designed with SOS inductor achieved more than 10 dBc/Hz reduction in phase noise and consumed half the power compared to VCO with MEMS inductor. Such low power VCO will improve battery life of a U...

2001 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems. Digest of Papers (IEEE Cat. No.01EX496), 2001

In this paper, impact of conventional silicon technology parameters on characteristics of passives is studied. For both inductors and capacitors, cost-effective modules, which integrate easily into wiring BEOL (Back-End Of Line) in a conventional silicon technology and provide high Q factor components are presented. For an inductor of 3 nH, designed for 2 GHz frequency applications, and fabricated in thick Cu as an add-on module, Q factor of ~24 is reached. The Metal Insulator Metal (MIM) capacitor module with outstanding RF performances and the Q factor ranging 100-1000 in the few GHz frequency range is developed in the Al BEOL. Compact lumped element SPICE models for both components are proposed and verified.

… and Guided Wave …, 1999

A novel h i g h 4 spiral inductor, implemented on a conductive Si wafer by applying the 3D MMlC structure over it, is proposed. The proposed inductor effectively uses a 10-pm-thick polyimide layers and ground plane with a window below the spiral.

Japanese Journal of Applied Physics, 2004

This paper presents the realization of a phenomenal Q-value increment as high as 122% for 4 nH spiral inductors on a silicon substrate. The loss mechanisms of parasitic effects on the Q-factor have been studied to improve Q design. The dramatic improvement in the Q value resulted from optimizing the doping level and film thickness of a poly shield layer combined with proton implantation. The shielding effect of poly-silicon and the semi-insulating characteristics of a proton-bombarded substrate have added 37% and 58% increments to the Q value of the inductors, respectively. The combination of the two methods has multiplied their individual contributions rather than just adding them. The technique proposed in this work shall become a critical measure for putting inductors on silicon substrates with superior performance for silicon-based radio frequency integrated circuit (RFIC) applications.

IEEE Transactions on Electron Devices, 1998

We present the extensive experimental results and their detailed analysis showing the important effects of layout parameters on the frequency responses of quality factor (Q) of rectangular spiral inductors, which are fabricated on a silicon substrate by using conventional silicon CMOS technology, in order to determine the desirable values of layout parameters for designing the high Q inductors used in RF IC's applications. Analysis of the inductors on Si substrates with three kinds of resistivities has been performed by tailoring the geometric layout and varying the metal thickness. Using these results, the substrate effects on RF performance of inductors are also investigated by observing the frequency responses of Q with varying the substrate resistivity in detail.

1998

A systematic method to improve the quality ( ) factor of RF integrated inductors is presented in this paper. The proposed method is based on the layout optimization to minimize the series resistance of the inductor coil, taking into account both ohmic losses, due to conduction currents, and magnetically induced losses, due to Eddy currents. The technique is particularly useful when applied to inductors in which the fabrication process includes integration substrate removal. However, it is also applicable to inductors on low-loss substrates. The method optimizes the width of the metal strip for each turn of the inductor coil, leading to a variable strip-width layout. The optimization procedure has been successfully applied to the design of square spiral inductors in a silicon-based multichip-module technology, complemented with silicon micromachining postprocessing. The obtained experimental results corroborate the validity of the proposed method. A factor of about 17 have been obtained for a 35-nH inductor at 1.5 GHz, with values higher than 40 predicted for a 20-nH inductor working at 3.5 GHz. The latter is up to a 60% better than the best results for a single strip-width inductor working at the same frequency.