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Metal-semiconductor-Metal (M-S-M) structure is widely used in electronic devices, which plays a key role in device performance. Here, we propose a simple and effective way to modulate the contact characteristics of aluminum (AI)-amorphous indium gallium zinc oxide (a-IGZO)-molybdenum (Mo) structure by applying local strain at the interface between Al layer and a-IGZO layer. Four types of I-V curves including forward rectifying, backward rectifying, linear and approximately symmetric are achieved under different pressures. Due to the nanoscale strain gradient induced by inhomogeneous local strain, flexoelectric potential is generated at the interface of the Al and the a-IGZO, which leads to the energy band bending. Therefore, the barrier height modulation can be realized. Meanwhile, the charges induced by flexoelectric effect in the a-IGZO layer can also modulate the barrier height at the a-IGZO/Mo interface. This work shows great potential to enhance the performance of electronic devices and it is promising for novel electromechanical applications. © 2021 IEEE.

Impedimetric and potentiometric biosensors have attracted considerable attention due to high sensitivity, high selectivity, rapid response time, low cost as well as miniaturization, and large numbers of them have been applied in the fields of pH detection, DNA detection, protein detection, cell analysis etc. However, compared with potentiometric field-effect transistor (FET) biosensors, impedimetric biosensors have the disadvantage of lower selectivity and they can not directly perform real-time detection. Meanwhile, there are still some limitations and challenges which have restricted the performance of FET-based biosensors at this moment, such as the limitation of Debye length screening. Based on the current development, this dissertation designed, fabricated and characterized the impedimetric and FET-based biosensors for biomolecule detection with high performance. An impedimetric polymer-based micro electrochemical sensor (PMES) was designed and fabricated to achieve rapid, label-free and cost-effective DNA detection. The relationship between device dimension and PMES’s sensitivity was studied, which revealed that the PMES with smallest dimension has shown best performance. The PMES chip has realized effective and rapid detection of DNA concentration with the sensitivity of 3.77 kΩ/nM and limit of detection (LOD) of 10 nM by the electrochemical impedance spectroscopy (EIS). Moreover, rapid label-free detection of Cordyceps sinensis (CorS) based on DNA hybridization by the PMES chip with the sensitivity of 7.94 kΩ/nM (2.48 kΩ·μl/ng) and the LOD of 720 pM (2.3 ng/μl) was successfully achieved. A dual-gate nanoribbon-based ion-sensitive field-effect transistor (NR-ISFET) biosensor for direct label-free DNA detection with high sensitivity was successfully designed, simulated and fabricated. Real-time conductance measurements of the NR-ISFET biosensors with different sample delivery configuration including a cavity and microchannel were conducted in solution-gate (SG

In this article, the static, dynamic, and short-circuit properties of 1.2-kV commercial 4H-SiC planar and trench gate metal-oxide-semiconductor field-effect transistors (MOSFETs) are compared and analyzed in a wide temperature range from 90 to 493 K. The temperature-dependent specific ON-resistance (Rsp-ON) and threshold voltage (V-th) are analyzed in relation to the density of the interface state. The turn-on rise and turn-off fall times (T-r and T-f) and the corresponding energy loss (E-r and E-f) are extracted from a double-pulse test from cryogenic to high temperature and analyzed. The short-circuit capability of the two structures is studied at low temperature for the first time. The comprehensive comparison and analysis of the planar and trench gate MOSFET versus temperature in this work show the importance to study applications with SiC MOSFETs in a wide temperature range, especially for the cryogenic temperatures., QC 20191203

In this paper, an improved 4H-SiC U-shaped trench-gate metal-oxide-semiconductor field-effect transistors (UMOSFETs) structure with low ON-resistance (R ON ) and switching energy loss is proposed. The novel structure features an added n-type region, which reduces ON-resistance of the device significantly while maintaining the breakdown voltage (V BR ). In addition, the gate of the improved structure is designed as a p-n junction to reduce the switching energy loss. Simulations by Sentaurus TCAD are carried out to reveal the working mechanism of this improved structure. For the static performance, the ON-resistance and the figure of merit (FOM = V BR 2 /R ON ) of the optimized structure are improved by 40% and 44%, respectively, as compared to a conventional trench MOSFET without the added n-type region and modified gate. For the dynamic performance, the turn-on time (T ON ) and turn-off time (T OFF ) of the proposed structure are both shorter than that of the conventional structure, bringing a 43% and 30% reduction in turn-on energy loss and total switching energy loss (E SW ). © 2019 IEEE.

In this paper, we propose a new 1D thermoresistive micro calorimetric flow (TMCF) sensor model for moist airflow with the temperature-dependent thermophysical properties. The 1D model and the corresponding proposed equivalent circuit model enable rapid design optimization of an ambient temperature-compensated TMCF ((TMCF)-M-2) sensor integrated with the interface circuit by using a commercial 0.35-mu m 2P4M CMOS MEMS technology. The fabricated sensor shows a prominent sensitivity of 0.543 V/(m/s) and a low power consumption of less than 2.8 mW. Moreover, in comparison with the large drifting of 49% for the uncompensated TMCF sensor, the (TMCF)-M-2 sensor's output has an ultralow drifting of 0.5% with the ambient temperature variation of 22 degrees C similar to 48 degrees C. Therefore, this robust (TMCF)-M-2 sensor can be a promising Internet of Things (IoT) for smart energy-efficient buildings.

We report on direct label-free protein detection in high ionic strength solution and human plasma by a dual-gate nanoribbon-based ion-sensitive field-effect transistor (NR-ISFET) biosensor system with excellent sensitivity and specificity in both solution-gate (SG) and dual-gate (DG) modes. Compared with previously reported results, the NR-ISFET biosensor enables selective prostate specific antigen (PSA) detection based on antibody-antigen binding in broader detection range with lower LOD. For the first time, real-time specific detection of PSA of 10 pM to 1 μM in 100 mM phosphate buffer (PB) was demonstrated by conductance measurements using the polyethylene glycol (PEG)-modified NR-ISFET biosensors in DG mode with the back-gate bias (VBG) of 20 V. Due to larger maximum transconductance value resulting from the modulation of NR-ISFET channel by the back gate in DG mode, the detection range can be broadened with larger linear detection region (100 pM to 100 nM) and lower limit of detection (LOD, 10 pM) as compared to those in SG mode. Moreover, the influence of different back-gate bias from VBG = 5 V to VBG = 25 V on the biosensor performance has been investigated. Furthermore, direct PSA detection of 100 pM to 1 μM in human plasma was demonstrated by using the PEG-modified NR-ISFET in DG mode, enabling direct detection of protein in human blood for clinical applications since the LOD of 100 pM PSA can meet the clinical requirements.

We report on in-situ protein detection in human plasma by a dual-gate nanoribbon-based ion-sensitive field-effect transistor (NR-ISFET) biosensor system with excellent sensitivity and specificity. For the first time, real-time detection of prostate specific antigen (PSA) of 10 pM to 1 μM in 100 mM phosphate buffer (PB) was demonstrated by conductance measurements using the polyethylene glycol (PEG)-modified NR-ISFET biosensors. Furthermore, direct PSA detection of 100 pM to 1 μM in human plasma was demonstrated by using the PEG-modified NR-ISFET, enabling direct detection of proteins in human blood for clinical applications. © 17CBMS-0001.

We report a dual-gate nanoribbon-based ion-sensitive field-effect transistor (NR-ISFET) biosensor system for direct label-free detection of Cordyceps sinensis's DNA (CorDNA). Compared with previous methods for CorDNA detection, the NR-ISFET biosensor shows smaller sample volume, lower detection concentration and shorter response time. Especially in dual-gate mode it exhibits a better sensitivity, the lower limit of detection, and improved specificity as compared to single solution-gate mode.

A general 1-D model was presented to predict the characteristics of CMOS thermoresistive micro calorimetric flow (TMCF) sensor with two types of packaging, i.e., open-space type and channel type, for both gases and liquids. The 1-D model was first validated by a numerical computational fluid dynamics (CFD) model and was subsequently normalized for different fluids flow. Notably, the model proposed by Nguyen and Dötzel is a special case of our 1-D model. The normalized output of TMCF sensor is a function of normalized input parameters of Reynolds number Re and Prandtl number Pr. The scaling analysis of the sensor output, sensitivity, and power consumption was performed to optimize the design of TMCF sensors in terms of key design parameters, including the thin film thickness, the height of bottom cavity, and so on. Accordingly, three pairs of TMCF sensors were designed and fabricated by using a 0.35 μm 2P4M CMOS microelectromechanical systems technology. The fabricated sensors showed a normalized sensitivity of 230 mV/(m/s)/mW for nitrogen gas flow, which was two orders of magnitude higher than the previous CMOS flow sensors. Therefore, the proposed 1-D model is a promising tool for the sensor's system-level design with the on-chip microelectronics for the Internet of Things. [2016-0098] © 2016 IEEE.

In this paper, a low-cost Temperature-compensated Thermoresistive Micro Calorimetric Flow (T2MCF) sensor by using a commercial 0.35μm 2P4M CMOS MEMS technology is reported. For nitrogen flow, the fabricated T2MCF sensor achieves a normalized sensitivity of 230 mV/(m/s)/mW with respect to the input heating power, which is two orders of magnitude better than the reported micro calorimetric flow sensors. The experimental results of T2MCF sensor under different ambient temperatures Ta of 22°C~48°C showed the excellent temperature insensitive output with the maximum normalized variation of 0.5%. Compared to the uncompensated counterpart (49%), it demonstrates our robust T2MCF sensor design is applicable for the integration of on-chip CMOS electronics for the Internet of Things.

Dimensional analysis was applied to systematically study the diffusion-limited (DL) and chargetransfer reaction-limited (CRL) processes in Micro electrochemical sensors (MECSs). The electrochemical impedance spectroscopy (EIS) for MECS to detect hydrogen and ammonium ions was fitted with the equivalent circuit model (ECM). With the help of Buckingham Pi Theorem, two dimensionless parameters: normalized impedance and reaction-diffusion-frequency were identified to distinguish these two processes. The results showed that these two parameters can be applied not only in our fabricated MECSs for detecting hydrogen and ammonium ions, but also in other reported relevant works for detecting copper ions and DNA molecules.

We report a low-cost Polymer-based Micro Electrochemical Sensor (PMES) system for the detection of the Cordyceps sinensis's DNA (CorDNA). With the electrochemical impedance spectroscopy (EIS), solution with different CorDNA concentrations can be significantly discriminated. Through the equivalent circuit model (ECM), CorDNA concentrations can be quantified by the solution resistance Rsol and double layer capacitance Cdl. The limit of detection (LOD) of PMES was 10 nM. Moreover, a portable electrochemical sensor system integrating MCU for CorDNA detection was built. Compared with conventional PCR-based methods, PMES has lower consumption sample volume of 5 μL, shorter response time and lower cost. © 15CBMS-0001.