Chen Yang

A Novel Pressure Microsensor With 30-

A novel pressure microsensor is designed, fabricated and tested. Novel piezoresistive sensing structures using 30- mum thick silicon diaphragms (from 370 mum times 370 mum to 970 mum times 970 mum ) and meander-shaped piezoresistors are devised. The diaphragms in this work thicker than that of the conventional piezoresistive pressure sensors extend the high-stress distribution into the bulk silicon and improve the device reliability. Piezoresistors are partially fabricated on the high-stress bulk silicon to obtain high sensitivity and linearity. Effects of different diaphragm areas, piezoresistor shapes, and placing methods on the sensing performances are simulated, measured, and analyzed. The whole fabrication is low-cost and compatible with standard IC process. Measurement shows promising results, i.e., large test region (0-1 MPa), high sensitivity (70.4 mV/VldrFS ), small linearity error (0.012%/FS) and good precision (0.16%/FS). The work indicates a novel solution of small size, high-performance, high-reliability, and low-cost pressure microsensor for tire pressure monitoring system and many other applications.

\mu \hbox{m}

We report the systematic study and design optimization of CMOS-compatible on-chip ferrite-integrated inductors, including detailed quantitative analysis by simulation and circuit modeling, new ferrite fabrication and characterization, ferrite-integrated-inductor design, measurement, and optimization. A new ferrite nanopowder-mixed-photoresist spin-coating/inkjetting technique is discussed. The design and characterization of ferrite-integrated inductors with various ferrite-filling structures are presented. Measurement shows substantial improvement of up to +160% in inductance (L) and + 220% in quality factor (Q) across the multigigahertz frequency spectrum with a self-resonance frequency (f 0) over 20 GHz for the new ferrite-integrated inductors. This study clearly suggests that the new ferrite-integrated inductor technique is a potential solution to the realization of radio-frequency systems-on-a-chip requiring high-performance compact on-chip inductors. This work is presented in two parts. Part I discusses the design and simulation of ferrite-integrated inductors. This paper is Part II, presenting experimental results for material research and device implementation.

-Thick Diaphragm and Meander-Shaped Piezoresistors Partially Distributed on High-Stress Bulk Silicon Region

This paper presents a new modeling technique, entitled extended MagPEEC model, which can be used to simulate arbitrary three-dimensional conductor-magnet structures of any geometry with direct conductor-magnet interfaces included. The new model was validated using a sample coaxial transmission line structure and was applied to investigate a group of super compact six-layer stacked spiral radio frequency integrated circuits (RFICs) inductor structures with various magnetic media integrated inside. This new modeling technique can be used to assist design of complex conductor-magnet structures including various magnetic-enhanced inductors for RFIC applications.

Investigation of On-Chip Soft-Ferrite-Integrated Inductors for RF ICs—Part II: Experiments

We report the design and analysis of the first vertical magnetic-cored inductors in CMOS backend for radio-frequency (RF) ICs, which includes theoretical and experimental studies of device architecture, equivalent circuit model with parameter extraction technique, process development, and device characterization. Vertical magnetic cores with multiple-layer stacked-spiral structures are designed to realize compact inductive devices in RF ICs. A CMOS-compatible post-CMOS backend process module (CMOS +) and optimized high-permeability nanoparticles are utilized to achieve a high inductance-to-coil-area ratio (L-density) in gigahertz range. The prototype six-layer inductors with NiZnCu ferrite nanoparticles-magnetic-core were fabricated in a commercial foundry 0.18-μm six-metal RF CMOS technology. A high L-density of over 700 nH/mm2 to multigigahertz was obtained, with an 80% chip size reduction from the reference planar magnetic inductors. An equivalent circuit model with parameter extraction technique is developed to analyze magnetic enhancement effects. This work demonstrates the potential of design and integration of compact high-performance vertical magnetic-cored inductive devices into CMOS backend for high-quality and low-cost RF systems-on-a-chip.

A new modeling technique for simulating 3-D arbitrary conductor-magnet structures for RFIC applications

We report a systematic investigation and design optimization of CMOS-compatible on-chip ferrite-integrated inductors, including a detailed quantitative analysis by simulation and circuit modeling, new ferrite material fabrication and characterization, and ferrite-integrated-inductor design, characterization, and optimization. A new ferrite nanopowder-mixed-photoresist spin-coating/inkjetting technique is discussed. The design and characterization of ferrite-integrated inductors with various ferrite-filling structures are presented. Measurement shows substantial improvement of up to +160% in inductance (L) and + 220% in quality factor (Q) across the multigigahertz frequency spectrum with a self-resonance frequency (f 0) of over 20 GHz for the new ferrite-integrated inductors. This paper clearly suggests that the new ferrite-integrated-inductor technique is a potentially viable solution to the realization of radio-frequency systems-on-a-chip requiring high-performance compact on-chip inductors. This work is presented in two parts. This paper is Part I, discussing the design and simulation of ferrite-integrated inductors. Part II discusses the experimental work, including material research and device implementation.

Design and Analysis of Vertical Nanoparticles-Magnetic-Cored Inductors for RF ICs

This paper reports fabrication of on-chip RF integrated inductors with spin-coated ferrite thin-films (Ni-Zn-Cu-Fe-O, Y-Bi-Fe-O and Co-Zr-O) and high-frequency characterization using equivalent circuit model. Measurement results show that, compared with air-cored inductor, the inductance (L) of Y-Bi-Fe-O and Co-Zr-O thin-film samples increases by 26-50% and 20-39% in 0.1-9GHz, respectively; while the quality factor (Q) of Co-Zr-O inductor is improved by 25-59%. This work demonstrates that the ferrite thin-films are promising for making high-performance integrated compact inductors for RF IC applications

Investigation of On-Chip Soft-Ferrite-Integrated Inductors for RF ICs—Part I: Design and Simulation

Several kinds of ferrite-integrated on-chip inductors are presented. Ferrite nanomaterial applied in RF on-chip inductors is prepared and analyzed to show the properties of high permeability, high ferromagnetic resonance frequency, high resistivity, and low loss, which has the potential that will improve the performance of RF on-chip inductors. Simulations of different coil and ferrite nanomaterial parameters, inductor structures, and surrounding structures are also conducted to achieve the trend of gains of inductance and quality factor of on-chip inductors. By integrating the prepared ferrite magnetic nanomaterial to the on-chip inductors with different structures, the measurement performances show an obvious improvement even in GHz frequency range. In addition, the studies of CMOS compatible process to integrate the nanomaterial promote the widespread application of magnetic nanomaterial in RF on-chip inductors.

On-Chip Integrated Inductors with Ferrite Thin-films for RF IC

This letter reports a novel concept of vertical stacked-spiral RF inductor with integrated nano-powder-magnetic-core in standard CMOS. A proof-of-concept design in a foundry 0.18 6-metal CMOS using a new post-CMOS backend process (CMOS+) is depicted. Measurement shows significant improvement in inductance of 35% and quality factor of 41% up to multi-GHz in prototype. An -density of 420 at 1.2 GHz is achieved. Limiting factors for the relatively low factor in the prototypes and improvement method are discussed.

Application of ferrite nanomaterial in RF on-chip inductors

Ferrite thin-film RF integrated inductors using IC compatible processes are proposed firstly. Ferrites (Co-based, CoFe-based, MnZn-based, NiZn-based and garnet) for RF integrated inductors are investigated, and CoZrO shows the suitable high-frequency performance for RF applications. Various inductors with different kinds of ferrite thin-films have been fabricated using fully integrated processes. A typical inductor sample with CoZrO thin-film is presented. The L and Q values of the sample are 2.05 nH and 20.5 at 2 GHz, respectively. The inductance is raised by 17% and the quality factor is raised by 41%, compared with the inductor which does not include a ferrite thin-film. With the improvement of L and Q, the size of ferrite thin-film inductors can be reduced significantly.

Stacked-Spiral RF Inductor With Vertical Nano-Powder Magnetic Core in CMOS

This paper presents on-chip planar inductors fully filled with magnetic-nano-particles-medium (MNPM) for compact and high-performance RF IC applications. In the prototype design, planar inductors have been constructed by using a filling process using nickel-ion permalloy (Ni80Fe17Mo3) of sub-100nm in diameter to increase the inductance while maintaining the magnetic performance for high-frequency circuitry. Preliminary results of stripline sample show more than 100% enhancement in inductance (L) with quality factor (Q) of about 20 up to 8GHz, which is very promising for RF ICs.