Ti Ohmic contacts to relatively highly doped (1 × 1018 cm−3) n-type 4H-SiC have been produced, without high temperature annealing, by means of low temperature electronic cyclotron resonance microwave hydrogen plasma pre-treatment (HPT) of the SiC surface. The as-deposited Ti/4H-SiC contacts show Ohmic properties, and the specific contact resistance obtained is as low as 2.07 × 10−4 Ω·cm2 after annealing at low temperatures (400 °C). This is achieved by low barrier height at Ti/SiC interface, which could be attributed to decrease of surface states density by the HPT releasing Fermi level pinning, and to band-gap narrowing, image-force, and thermionic-field emission at high doping.

Although silicon carbide (SiC) metal oxide semiconductor field-effect transistors (MOSFETs) are commercially available, bias temperature instability (BTI) defined as shifts in V _th in SiC MOSFET and V _fb in MOS capacitor after the device is operated at a high temperature, seriously affects device reliability and limits further commercial applications. These instabilities are mainly attributed to charge trapping at and near the SiC/SiO ₂ interface and mobile ions in a gate oxide. The consequences of V _th instability are serious and can worsen the performance and lifetime of SiC MOS devices. In this review, the SiC/SiO ₂ interface issue is introduced, and BTI occurring in current SiC MOS devices is described in detail. V _th / V _fb instability behavior induced by measurement and stress conditions, microscopic defects and instability mechanisms, recent measurement techniques of near-interfacial oxide traps, and BTI improvement resulting from the fabrication processes are described. BTI improvement mainly involves the control of charge trapping and movements of ions. The fabrication processes are related to oxidation and pre- and post-oxidation treatments. This review can help deepen our understanding of BTI and reduce its influence on SiC MOS devices performance.

The chemical structure of SiO2/4H-SiC (0001) interface transition region is investigated using angle-dependent x-ray photoelectron spectroscopy. The relative intensities of various silicon oxycarbides (SiOxCy) components as a function of polar emission angle suggest that SiOC3, SiO2C2, SiO3C, and SiO2 have different depth distributions at the interface. Then a nonabrupt four-layer structure model is proposed. And the relative intensities of various SiOxCy species are fitted based on the model by an electron damping scheme. The well fitted results indicate that the SiO2/4H-SiC (0001) interface transition region can be described by a chemically nonabrupt four-layer structure model well.

This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.