Study on adhesion and electro-optical properties of ITO films on flexible PET substrate

High-quality ITO films on flexible PET substrate were prepared by RF magnetron sputtering at low deposition temperature with different Ar gas sputtering pressure. Adhesion and electro-optical properties of ITO films were investigated as a function of Ar partial pressure. The sputtering conditions provide very uniform ITO films with high transparency (>85% in 400-760 nm spectra) and low electrical resistivity (1.408×10-3-1.956×10-3 Ω·cm). Scratch test experiments indicate that there is a good adhesion property between ITO films and PET substrate, the critical characteristic load increases from 16.5 to 23.2 N with increasing Ar sputtering pressure from 0.2 to 1.4 Pa.

Few-layered ReS_2 nanosheets grown on graphene as electrocatalyst for hydrogen evolution reaction

Few-layered ReStwo-dimensional(2 D) semiconductor nanosheets directly nucleated and grown on reduced graphene oxide(RGO) were synthesized through a facile hydrothermal method. Compared with bare ReS, the ReS2/RGO hybrid delivers much better electrocatalytic activity for hydrogen evolution reaction(HER) in acidic media. It exhibits a lower Tafel slope of 107.4 mV decand a larger current density of-5.2 mA·cmat-250 mV(vs. RHE),compared with ReS(152.7 mV·dec,-3.1 mA·cm). The ReS/RGO hybrid has a unique architecture constructed by highly conductive and porous RGO internetworks, which guarantees easy electrolyte infiltration and efficient charge transfer and provides sufficient active edge sites, resulting in enhanced HER performance. The present synthesis approach can be extended to synthesize other 2 D-semiconductor-based composites for energy storage and catalytic devices.

A novel DTSCR with a variation lateral base doping structure to improve turn-on speed for ESD protection

The turn-on speed of electrostatic discharge （ESD） protection devices is very important for the protection of the ultrathin gate oxide. A double trigger silicon controlled rectifier device （DTSCR） can be used effectively for ESD protection because it can turn on relatively quickly. The turn-on process of the DTSCR is first studied, and a formula for calculating the turn-on time of the DTSCR is derived. It is found that the turn-on time of the DTSCR is determined mainly by the base transit time of the parasitic p-n-p and n-p-n transistors. Using the variation lateral base doping （VLBD） structure can reduce the base transit time, and a novel DTSCR device with a VLBD structure （VLBD_DTSCR） is proposed for ESD protection applications. The static-state and turn-on characteristics of the VLBD DTSCR device are simulated. The simulation results show that the VLBD structure can introduce a built-in electric field in the base region of the parasitic n-p-n and p--n-p bipolar transistors to accelerate the transport of free-carriers through the base region. In the same process and layout area, the turn-on time of the VLBD DTSCR device is at least 27% less than that of the DTSCR device with the traditional uniform base doping under the same value of the trigger current.

A novel HBT trigger SCR in 0.35 μm SiGe BiCMOS technology

The silicon-controlled rectifier（SCR） device is known as an efficient electrostatic discharge（ESD） protection device due to the highest ESD robustness in the smallest layout area. However, SCR has some drawbacks,such as high trigger voltage and low holding voltage. In order to reduce the trigger voltage of the SCR device for ESD protection, a new heterojunction bipolar transistor（HBT） trigger silicon controlled rectifier（HTSCR） device in 0.35 m Si Ge Bi CMOS technology are proposed. The underlying physical mechanisms critical to the trigger voltage are demonstrated based on transmission line pulsing（TLP） measurement and physics-based simulation results. The simulation results prove that the trigger voltage of the HTSCR is decided by the collector-to-emitter breakdown voltage of the HBT structure in floating base configuration. The ESD experiment test results demonstrate the HTSCR can offer superior performance with a small trigger voltage, an adjustable holding voltage and a high ESD robustness. In comparison to the conventional MLSCR, the trigger voltage of the fabricated HTSCR can reduce to less than 50% of that of the MLSCR, and the I_（t2） of the HBT trigger SCR is 80% more than that of the MLSCR.