Multimodal behavior of the dynamic magnetic susceptibility spectrum in amorphous CoZrTaB magnetic thin films

The origins of sub-Ferromagnetic Resonance (FMR) multimodal behavior in the magnetic susceptibility spectrum of amorphous CoZrTaB magnetic thin films are investigated using Brown's diffusion model describing continuous diffusion of magnetic spins. Brown's diffusion model is regressed onto experimental data for the amorphous CoZrTaB magnetic thin films with thicknesses spanning 80-530nm. The mathematical model presented successfully reproduces the thickness dependent dynamic magnetic susceptibility of the amorphous CoZrTaB magnetic thin films with strong statistical significance. The model proposes the formation of additional energy wells in the uniaxial anisotropy energy plane of the material after a critical film thickness. The sub-FMR resonance peaks arise when the frequency of the external excitation field approaches the natural frequency of the well. Furthermore, the additional energy wells in the anisotropy energy plane cause a breakdown in the axial symmetry of the anisotropy energy plane. This breakdown of axial symmetry results in dynamic coupling between the transverse (chi(perpendicular to)) and longitudinal (chi(parallel to)) magnetic susceptibility. This dynamic coupling results in the initial low frequency step-down in the magnetic susceptibility observed in the thicker CoZrTaB magnetic thin films. It is found that the application of an external bias magnetic field along the easy axis of the amorphous CoZrTaB magnetic thin films suppresses the sub-FMR resonance peaks by restoring the axial symmetry of the anisotropy energy plane

Methods for latent image simulations in photolithography with a polychromatic light attenuation equation for fabricating VIAs in 2.5D and 3D advanced packaging architectures

As demand accelerates for multifunctional devices with a small footprint and minimal power consumption, 2.5D and 3D advanced packaging architectures have emerged as an essential solution that use through-substrate vias (TSVs) as vertical interconnects. Vertical stacking enables chip packages with increased functionality, enhanced design versatility, minimal power loss, reduced footprint and high bandwidth. Unlocking the potential of photolithography for vertical interconnect access (VIA) fabrication requires fast and accurate predictive modeling of diffraction effects and resist film photochemistry. This procedure is especially challenging for broad-spectrum exposure systems that use, for example, Hg bulbs with g-, h-, and i-line UV radiation. In this paper, we present new methods and equations for VIA latent image determination in photolithography that are suitable for broad-spectrum exposure and negate the need for complex and time-consuming in situ metrology. Our technique is accurate, converges quickly on the average modern PC and could be readily integrated into photolithography simulation software. We derive a polychromatic light attenuation equation from the Beer-Lambert law, which can be used in a critical exposure dose model to determine the photochemical reaction state. We integrate this equation with an exact scalar diffraction formula to produce a succinct equation comprising a complete coupling between light propagation phenomena and photochemical behavior. We then perform a comparative study between 2D/3D photoresist latent image simulation geometries and directly corresponding experimental data, which demonstrates a highly positive correlation. We anticipate that this technique will be a valuable asset to photolithography, micro- and nano-optical systems and advanced packaging/system integration with applications in technology domains ranging from space to automotive to the Internet of Things (IoT)

Comprehensive design procedure for racetrack microinductors

Present needs in efficiency and integration are driving research towards the miniaturization of power converters. Among the latest components to achieve the desired degree of integration are cored micro-inductors and they are still one of the hardest devices to optimize, due to the high number of freedom degrees in their fabrication. In this paper, a comprehensive design procedure for these micro-inductors is presented. The proposed method makes it possible to design the optimal device in a single iteration. It also allows the designer to easily ascertain the limits of the inductor in terms of handled current and losses and provides valuable physical insight on the output of the process

High-Q 3D Microfabricated Magnetic-core Toroidal Inductors for Power Supplies in Package

Integration of power inductors is a roadblock in realizing highly miniaturized power supply in package (PwrSiP) and power supply on chip (PwrSoC). Inductors in such power system are used for energy storage and filtering, but they dominate in size and loss. This paper presents a novel 3D through-silicon via (TSV) magnetic-core toroidal inductor for PwrSiP. The magnetic-powder-based core is embedded into TSV air-core inductor using a casting method. The unique air-core inductor design with a hollow core and suspended windings enable a complete core filling with microscale magnetic powders. TSV magnetic-core inductors are fabricated in a compact size of 2.4 x 2.4 x 0.28 mm with the core content varying from 63 to 88 weight percent of soft ferrite NiZn powders. Small-signal measurements show a three-fold higher inductance of 112 nH and a 30% higher quality factor of 14.3 at 12.5 MHz for TSV magnetic-core inductors compared to similar TSV air-core inductors. The results are verified by the modelled results. The total core loss is characterized by large-signal measurements. A suitable inductor is implemented in a zero-voltage-switching 12-MHz buck converter. The converter achieves a peak efficiency of 72% and the output power of 2.4 W converting 12 to 5 VDC

PCB embedded toroidal inductor for 2MHz point-of-load converter

Increasing switching frequency, enabled by advances in discrete silicon switches, monolithic CMOS/LDMOS switching bridges and GaN HEMTs, have resulted in a lower inductance requirement for the DC-DC power converter. High density, high efficiency magnetic materials are required to support the increasing power semiconductor switching frequencies. Advanced packaging technologies allow magnetic devices to be integrated within the package substrate of the application Printed Circuit Board (PCB). This paper provides an overview of the magnetic core embedding process technology and a procedure to characterise the magnetic material after its co-processing during the PCB manufacturing process

The clarity modular ambient health and wellness measurement platform

Paper presented at the Fourth International Conference on Sensor Technologies and Applications (NetWare 2010 - SENSORCOMM 2010), Venice, Italy July 2010Emerging healthcare applications can benefit enormously from recent advances in pervasive technology and computing. This paper introduces the CLARITY Modular Ambient Health and Wellness Measurement Platform, which is a heterogeneous and robust pervasive healthcare solution currently under development at the CLARITY Center for Sensor Web Technologies. This intelligent and context-aware platform comprises the Tyndall Wireless Sensor Network prototyping system, augmented with an agent-based middleware and frontend computing architecture. The key contribution of this work is to highlight how interoperability, expandability, reusability and robustness can be manifested in the modular design of the constituent nodes and the inherently distributed nature of the controlling software architecture.Science Foundation IrelandConference detailshttp://www.iaria.org/conferences2010/SENSORCOMM10.htmlOn publication, swap submitted version with published version and add set text - contact AV - 7/10/2010. au ti ke SB. 11/10/201

Microscopic gel-liquid interfaces supported by hollow microneedle array for voltammetric drug detection

International audienceThis report describes a method for integration of a gel-liquid interface in hollow microneedles compatible with minimally invasive, electrochemical detection of drugs in vivo. The electrochemical sensor was characterised using cyclic voltammetry with tetraethyl ammonium. The experimental work demonstrated the detection of propranolol as a representative drug in physiological buffer with the microneedle system. A calibration curve for propranolol was built from measurements with differential pulse stripping voltammetry, indicating a sensitivity of 43 nA mu M-1, a limit of detection of 50 nM and a linear range between 50 and 200 nM

Modeling, Design, and Fabrication of High Inductance Bond Wire Micro-Transformers with Toroidal Ferrite Core

This paper presents the design of miniaturized bond wire transformers assembled with standard IC bonding wires and NiZn and MnZn ferrite toroidal cores. Several prototypes are fabricated on a PCB substrate with various layouts in a 4.95 mm × 4.95 mm area. The devices are modeled by analytical means and characterized with impedance measurements over a wide frequency range. Experimental results on 1 : 38 device show that the secondary self-inductance increases from 0.3 uH with air-core to 315 uH with ferrite core; the coupling coefficient improves from 0.1 with air-core to 0.9 with ferrite core; the effective turns ratio enhances from 0.5 with air-core to 34 with ferrite core. This approach is cost-effective and enables a flexible design of efficient micro-magnetics on-top of ICs with DC inductance to resistance ratio of 70 uH/Ohm and an inductance per unit area of 12.8 uH/mm^2 up to 0.3 MHz. The design targets the development of bootstrap circuits for ultra-low voltage energy harvesting. In this context, a low voltage step-up oscillator suitable for TEG sources is realized with a commercial IC and the proposed micro-transformers. Experimental measurements on a discrete prototype report that the circuit bootstraps from voltages down to 260 mV and outputs a DC voltage of 2 V

Thin-film magnetics-on-silicon integrated transformer for isolated signal and power coupling applications

Smart Switches for future generation power systems will be realised by densely integrating GaN switches with CMOS drive and control logic, enabling higher switching frequencies, greater efficiency and smart gate driver features such as for improved switch protection and offering improved control telemetry. The realization of such systems will benefit from the integration of power coupling and signal isolating transformers, either on-chip or at package-level. This work reports the development of a thin-film magnetics-on-silicon (MoS) micro-transformer for functional (operational grade insulation) galvanic isolation of the gate drive logic signal. The micro-transformer will be integrated with GaN switches and CMOS logic circuits to implement applications such as high frequency resonant LLC converter, in lower voltage applications, such as for 12, 24 or 48V systems