A handheld high-sensitivity micro-NMR CMOS platform with B-field stabilization for multi-type biological/chemical assays

We report a micro-nuclear magnetic resonance (NMR) system compatible with multi-type biological/chemical lab-on-a-chip assays. Unified in a handheld scale (dimension: 14 x 6 x 11 cm³, weight: 1.4 kg), the system is capable to detect<100 pM of Enterococcus faecalis derived DNA from a 2.5 μL sample. The key components are a portable magnet (0.46 T, 1.25 kg) for nucleus magnetization, a system PCB for I/O interface, an FPGA for system control, a current driver for trimming the magnetic (B) field, and a silicon chip fabricated in 0.18 μm CMOS. The latter, integrated with a current-mode vertical Hall sensor and a low-noise readout circuit, facilitates closed-loop B-field stabilization (2 mT → 0.15 mT), which otherwise fluctuates with temperature or sample displacement. Together with a dynamic-B-field transceiver with a planar coil for micro-NMR assay and thermal control, the system demonstrates: 1) selective biological target pinpointing; 2) protein state analysis; and 3) solvent-polymer dynamics, suitable for healthcare, food and colloidal applications, respectively. Compared to a commercial NMR-assay product (Bruker mq-20), this platform greatly reduces the sample consumption (120x), hardware volume (175x), and weight (96x)

Three-dimensional magnetic field sensor in IBM 0.18μm CMOS technology

This work presents a compact three-dimensional Magnetic Field Sensor (MFS) designed in standard Complementary Metal-Oxide-Semiconductor (CMOS) technology. A circular Vertical Hall Device (VHD) for horizontal magnetic field detection and a split- drain Horizontal Hall Device (HHD) for the vertical magnetic field detection are integrated to implement the three-dimensional M FS. This merged design has the advantage of smaller area and lower power consumption. The sensitivity of the vertical hall device (ring-shaped magneto-resistor) and the horizontal hall device (Split-Drain Magnetic Field-Effect Transistor (SD-MAGFET)) is estimated as 0.11V/T and 2.88V/T respectively. The vertical direction of the magnetic field detection demonstrates a higher sensitivity. A high gain cascode differential amplifier is integrated with the sensor to further amplify the magnetic signal

Device modelling for bendable piezoelectric FET-based touch sensing system

Flexible electronics is rapidly evolving towards devices and circuits to enable numerous new applications. The high-performance, in terms of response speed, uniformity and reliability, remains a sticking point. The potential solutions for high-performance related challenges bring us back to the timetested silicon based electronics. However, the changes in the response of silicon based devices due to bending related stresses is a concern, especially because there are no suitable models to predict this behavior. This also makes the circuit design a difficult task. This paper reports advances in this direction, through our research on bendable Piezoelectric Oxide Semiconductor Field Effect Transistor (POSFET) based touch sensors. The analytical model of POSFET, complimented with Verilog-A model, is presented to describe the device behavior under normal force in planar and stressed conditions. Further, dynamic readout circuit compensation of POSFET devices have been analyzed and compared with similar arrangement to reduce the piezoresistive effect under tensile and compressive stresses. This approach introduces a first step towards the systematic modeling of stress induced changes in device response. This systematic study will help realize high-performance bendable microsystems with integrated sensors and readout circuitry on ultra-thin chips (UTCs) needed in various applications, in particular, the electronic skin (e-skin)

Hall probes: physics and application to magnetometry

This lecture aims to present an overview of the properties of Hall effect devices. Descriptions of the Hall phenomenon, a review of the Hall effect device characteristics and of the various types of probes are presented. Particular attention is paid to the recent development of three-axis sensors and the related techniques to cancel the offsets and the planar Hall effect. The lecture introduces the delicate problem of the calibration of a three-dimensional sensor and ends with a section devoted to magnetic measurements in conventional beam line magnets and undulators.Comment: 40 pages, presented at the CERN Accelerator School CAS 2009: Specialised Course on Magnets, Bruges, 16-25 June 200

Three dimensional magnetic field sensors and array in BiCMOS technology

This thesis presents new designs of three dimensional magnetic field sensors in BiCMOS technology. The detailed design of the merged structure device by common diffusion and the high gain transduction circuit are presented. The merged structure has the advantage of less area, less external contacts and less parasitic capacitance. Cross-sensitivity is also eliminated by employing the merged structure. Three active on-chip loads are introduced to improve the sensitivity. The SPICE simulation results show that when a relative change in current ΔI/I is 0.001, about 13.6 mV and 8.5mV can be detected at the output in X(or Y) and Z directions, respectively. The experimental results from a standard (non-merged) BiCMOS magnetic sensor is presented. The 3-D sensor element has been integrated with the signal processing circuits to build a monolithic 8 x 8 sensor array. The detailed SPICE simulation results on the critical path shows the array can be operated with elimination of column-to-column offset voltages under a maximum scanning clock speed of about 0.5MHz. The array structure can find application in precise manufacturing as a position sensor

Infrastructure for Detector Research and Development towards the International Linear Collider

The EUDET-project was launched to create an infrastructure for developing and testing new and advanced detector technologies to be used at a future linear collider. The aim was to make possible experimentation and analysis of data for institutes, which otherwise could not be realized due to lack of resources. The infrastructure comprised an analysis and software network, and instrumentation infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture

Ultra-thin silicon based piezoelectric capacitive tactile sensor

This paper presents an ultra-thin bendable silicon based tactile sensor, in a piezoelectric capacitor configuration, realized by wet anisotropic etching as post-processing steps. The device is fabricated over bulk silicon, which is thinned down to 35 μm from an original thickness of 636 μm. Dicing of thin membrane is achieved by low cost novel technique of Dicing before Etching. The piezoelectric capacitor is composed of polyvinylidene fluoride trifluoroethylene (PVDF-TrFE), which present an attractive avenue for tactile sensing as they respond to dynamic contact events (which is critical for robotic tasks), easy to fabricate at low cost and are inherently flexible. The sensor exhibits enhanced piezoelectric properties, thanks to the optimization of the poling procedure. The sensor capacitive behaviour is confirmed using impedance analysis and the electro-mechanical characterization is done using TIRA shaker setup