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This work presents a CMOS capacitive biosensor array for detection of the pathogenic avian influenza virus DNA. Sensing resolution is significantly enhanced by monolithic integration to reduce the parasitic effect and the use of a thin dielectric layer as the sensing interface. The array contains both planar and interdigitated electrode designs with the same CMOS readout to compare their sensing capabilities...
Liquid properties can be studied by monitoring the in-liquid resonant behavior of micromechanical devices. Most of these devices are electromagnetically or piezoelectrically driven to oscillation and rely on externally sensed signals to sustain oscillation. This work presents the first attempt to implement capacitive micromechanical oscillators on a CMOS (complementary metal-oxide-semiconductor) chip...
Pulse diagnosis is one of major methods used in traditional Chinese medicine to evaluate a patient's health conditions. Development of a pulse diagnosis apparatus can lead to modernization and advancement of the field by providing more objective and accurate evaluations. This study aims at demonstrating real-time pulse measurement by using the developed flexible capacitive pressure sensors. A 5 ×...
A bi-axial scanning micromirror is typically used for scanning-type projectors to receive and deflect laser beams to form two-dimensional images pixel by pixel. The operation requires the micromirror to be driven at its resonant frequency which can vary due to fabrication tolerance and temperature drift, necessitating the use of a closed-loop oscillator circuit. This study reports capacitive driving...
Magnetic microbeads are widely used in biotechnology and biomedical research for manipulation and detection of cells and biomolecules. Most lab-on-chip systems capable of performing manipulation and detection require external instruments to perform one of the functions, leading to increased size and cost. This work aims at developing an integrated platform to perform these two functions by implementing...
Magnetic microbeads are widely used in biotechnology and biomedical research for manipulation and detection of cells and biomolecules. This work presents an integrated platform to perform microbead-based manipulation and detection by implementing electromagnetic microcoils and capacitive biosensors on a CMOS (complementary metal oxide semiconductor) chip. Our detection method provides the advantages...
While resonant sensing has been applied to detect various physical or chemical quantities, many reported sensing systems are still bulky and expensive as they rely on external instruments to conduct measurements. For practical applications, it is often desirable to have a low-cost miniaturized sensor chip with multiple sensing devices to validate a sensing event. This work presents the first attempt...
Three dimensional (3-D) photoacoustic imaging is demonstrated in this study by using a 4 × 4 CMOS (complementary metal oxide semiconductor) micromachined capacitive ultrasonic sensor array. The sensing membranes are fabricated by a post-CMOS metal etch and sealed by parylene with a measured resonant frequency between 3 to 5.1 MHz. The area of a single detection unit is 280 × 280 μm2. A large 2-D aperture...
The glass-based low-temperature polycrystalline-silicon (LTPS) thin-film transistor (TFT) process, as widely known for making liquid crystal displays, is utilized in this work to realize a fully integrated, microbead-based micro-manipulation and biosensing platform. The operation utilizes arrays of microelectrodes made of transparent iridium tin oxide (ITO) to move the immobilized polystyrene microbeads...
This work describes the design and characterization of integrated CMOS (complementary metal oxide semiconductor) oscillators comprising of a capacitively transduced micromechanical resonator and a phase-locked loop (PLL) driving circuit. Inclusion of a PLL is beneficial for sustaining oscillations at resonant frequencies within the PLL capture range. The micromechanical resonator has a measured resonant...
This work presents miniaturized CMOS (complementary metal oxide semiconductor) impedimetric sensors for detection of avian influenza virus (AIV) in the femtomolar level. The sensing resolution is significantly enhanced owing to monolithic sensor integration to reduce the parasitic effect and the use of sub-μm interdigitated microelectrodes to promote signal coupling efficiency. The 4×4 sensor array...
Biometric techniques, such as fingerprint detection, can be applied to identify a specific user for security and safety reasons. We present a capacitive fingerprint sensor that can detect the difference of pressures induced by the ridges and valleys of a finger tip. Post-CMOS fabrication of the 8×32 sensor array is conducted based on wet etch of CMOS metal layers without requiring additional thin-film...
In this study, we demonstrate the feasibility of three dimensional (3-D) photoacoustic imaging using a monolithic CMOS MEMS capacitive ultrasonic sensor. The sensing membranes are released by a post-CMOS metal etch and sealed by silicon dioxide. Nine membranes, each with an inner diameter of 60 µm, form a single detection unit with a capacitance value of 292.5 fF. The measured sensitivity is 151 mV...
This work presents the design and characterization of an integrated CMOS (complementary metal oxide semiconductor) electrochemical sensor array for dopamine (DA) detection. The chip is intended to provide as a platform for high-throughput measurement of neurotransmitter release during exocytosis. Interdigitated gold microelectrodes with a 5-µm gap are fabricated on CMOS chips by a post-CMOS lithographic...
The glass-based LTPS (low temperature polysilicon) TFT (thin-film transistor) process, as widely known for making liquid crystal displays, is utilized for the first time to make CMOS capacitive sensors for dopamine detection. Dopamine plays important roles in human behavior, cognition, and motor activity. The interface capacitance change, after its binding with 4-carboxyphenylboronic acid (CPBA),...
Open-gate ion-sensitive field-effect transistors (ISFET) are presented in this work to provide real-time ultrasensitive dopamine (DA) detection in the femto-molar (fM) range. The polysilicon gates of p-type FETs fabricated in a 0.35-μm CMOS (complementary metal-oxide-semiconductor) process were removed by a convenient post-CMOS process to expose the gate oxide for surface functionalization...
This work presents an 8 × 8 CMOS thermal sensor array for real-time, localized detection of the thermal energy produced by enzyme-catalyzed glucose reaction. The current of the PMOS sensing transistor is converted to a sawtooth-like waveform whose slope increases with respect to the temperature. Each of the sensing transistors occupies an area of 25 μm by 23 μm, which...
An integrated high-sensitivity CMOS MEMS capacitive accelerometer with thermal stability has been designed and demonstrated in this work. Issue of obtaining stable DC bias at input terminals is particularly addressed. Sensitivity of 595 mV/g is achieved in the accelerometer and the overall noise floor is 50 μg/√Hz, which corresponds to an effective capacitance noise floor of 0.024 aF/√Hz. The zero-g...
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