A rating voltage of 150 and 200 V split-gate trench (SGT) power metal-oxide- semiconductor field-effect transistor (Power MOSFET) with different epitaxial layers was proposed and studied. In order to reduce the specific on-resistance (Ron,sp) of a 150 and 200 V SGT power MOSFET, we used a multiple epitaxies (EPIs) structure to design it and compared other single-EPI and double-EPIs devices based on the same fabrication process. We found that the bottom epitaxial (EPI) layer of a double-EPIs structure can be designed to support the breakdown voltage, and the top one can be adjusted to reduce the Ron,sp. Therefore, the double-EPIs device has more flexibility to achieve a lower Ron,sp than the single-EPI one. When the required voltage is over 100 V, the on-state resistance (Ron) of double-EPIs device is no longer satisfying our expectations. A triple-EPIs structure was designed and studied, to reduce its Ron, without sacrificing the breakdown voltage. We used an Integrated System Engineering-Technology Computer-Aided Design (ISE-TCAD) simulator to investigate and study the 150 V SGT power MOSFETs with different EPI structures, by modulating the thickness and resistivity of each EPI layer. The simulated Ron,sp of a 150 V triple-EPIs device is only 62% and 18.3% of that for the double-EPIs and single-EPI structure, respectively.
Photodetectors and gas sensors are vital in modern technology, spanning from environmental monitoring to biomedical diagnostics. This paper explores the UV detection and gas sensing properties of a zinc oxide (ZnO) nanorod array (ZNA) grown on silver nanowire mesh (AgNM) using a hydrothermal method. We examined the impact of different zinc acetate precursor concentrations on their properties. Results show the AgNM forms a network with high transparency (79%) and low sheet resistance (7.23 Ω/□). A sol–gel ZnO thin film was coated on this mesh, providing a seed layer with a hexagonal wurtzite structure. Increasing the precursor concentration alters the diameter, length, and area density of ZNAs, affecting their performance. The ZNA-AgNM-based photodetector shows enhanced dark current and photocurrent with increasing precursor concentration, achieving a maximum photoresponsivity of 114 A/W at 374 nm and a detectivity of 6.37 × 1014 Jones at 0.05 M zinc acetate. For gas sensing, the resistance of ZNA-AgNM-based sensors decreases with temperature, with the best hydrogen response (2.71) at 300 °C and 0.04 M precursor concentration. These findings highlight the potential of ZNA-AgNM for high-performance UV photodetectors and hydrogen gas sensors, offering an alternative way for the development of future sensing devices with enhanced performance and functionality.
Tungsten-doped TiO2 thin films were prepared by sol–gel method on fluorine-doped tin oxide-coated substrates as working electrodes of dye-sensitized solar cells. The influences of different W doping (0, 2, 4, 6, and 8 at%) on the microstructure, optical, and photovoltaic properties of the W-TiO2 thin-film DSSCs were studied by the measurement of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, and electrochemical impedance spectroscopy (EIS). An optimal DSSCs performance was observed with a 6 at% W-doped TiO2 thin film, resulting in a Voc of 0.68 V, a Jsc of 20.2 mA/cm2, an FF of 68.6%, and an efficiency (η) of 9.42%. The efficiency of DSSCs with 6 at% W-doped TiO2 photoanode improved by 75%. This is because the 6 at% W-doped TiO2 thin film increases the specific surface area and electron transfer rate.
18 May 2016 in IEEE Transactions on Electron Devices
A new multiple-gate poly-Si thin-film transistor (TFT) with a bottom field plate (FP) is proposed. The FP disperses the high current density away from the top corner of the spacer channel with the highest electric field, leading to an improved kink effect. Moreover, owing to an inversion layer induced by the FP at the bottom region of spacer poly-Si channel, a higher on-state current is achieved. In addition, the electric field near drain area is reduced, leading to a lower off-state current. Overall, the new multiple-gate poly-Si TFT shows improved characteristics as compared with the counterpart without a bottom FP.
In this letter, gate-all-around (GAA) polycrystalline silicon thin-film transistors (TFTs) with self-aligned grain-growth channels were fabricated using excimer laser crystallization (ELC) on a recessed-nanowire (RN) structure. Via the RN structure constructed by a simple sidewall-spacer formation, location-controlled nucleation and volume-confined lateral grain growth within the RN body during ELC process have been demonstrated with only one perpendicular grain boundary in each nanowire channel. Because of the high-crystallinity channel together with GAA operation mode, the proposed GAA-RN TFTs show good device integrity of lower threshold voltage, steeper subthreshold slope, and higher field-effect mobility as compared with the conventional planar counterparts.