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In this article, we report the first experimental results of a novel 4H-silicon carbide (SiC) p-i-n photodetector based on a vertical nanocone array (NCA). It is fabricated by electron beam lithography and inductively coupled plasma (ICP) etching technology. The performance of static and dynamic behavior was studied systematically. It shows the responsivity of ~41.9 mA/W under 360 nm at a bias voltage of -0.5 V and has a linear response to the ultraviolet (UV) light in a wide light intensity range of 0.1-10⁴ mW/cm². The response time decreased as the light intensity rose from 3 mW/cm² to 5 W/cm² and then leveled off at higher light intensity (>100 mW/cm²), which is about 0.25 ms. The photodetector -3-dB cutoff is ~3400 Hz at λ = 360 nm and light intensity = 100 mW/cm². Besides, the detector can respond to the UV light from 260 to 360 nm and the peak responsivity is ~78 mA/W at 320 nm. The analysis results have reference values for the development of an innovative 4H-SiC UV photodetector to some extent.

A novel post-oxidation annealing (POA) process with supercritical N2O (SCN2O) fluid is reported to be highly effective in improving the interface properties of the SiO2/4H–silicon carbide (SiC) (0001) systems. After SCN2O POA, the interface state density reduces to $2.8 \times 10^{{11}}$ eV−1cm−2, which is about 3.5 times lower than that after a traditional high-temperature N2O POA process. Meanwhile, the highest oxide critical electric field shows an increase of 18.19% and the near-interfacial oxide traps is reduced by 69.90% compared with that after N2O POA process. The process temperature is as low as 120 °C. The significantly reduced processing temperature avoids additional defect generation while the supercritical state provides a stronger nitridation effect. SCN2O annealing is a promising candidate for POA process toward high-performance SiC power metal-oxide-semiconductor field effect transistors (MOSFETs).

Surface treatment is quite vital to reduce the reverse leakage current and improve the current On–Off ratio of gallium nitride (GaN) quasi-vertical Schottky barrier diode (SBD). In this work, we report a new nondestructive low temperature supercritical CO2 fluid (SCF) nitridation technology to treat the surface of GaN and substantially reduce the leakage current of GaN quasi-vertical SBD. The X-ray photoelectron spectroscopy (XPS) reveals the increased nitriding degree and oxygen doping degree in the form of GaO x after the SCF process results in the leakage performance improvement. As a result, the defects at metal/semiconductor interface are passivated. Also, because of NH-2 and OH− generated from the SCF process, the surface peak electric field of n−GaN decreases, and thus the breakdown voltage is enhanced. The reverse leakage current density is reduced by more than three orders of magnitude from $3.7\times 10^{-{6}}$ to $3.52\times 10^{-{9}}$ A/cm2 (at −3 V) and the ON-/ OFF-current ratio is improved by three orders from $8\times 10^{{7}}$ to $5.74\times 10^{{10}}$ .

Considering potential applications related to superconductivity and aerospace (typically less than 100 K), in this article, the temperature dependence of silicon carbide (SiC) power diodes is systematically characterized and analyzed over a wide temperature range of 90–478 K, especially focusing on cryogenic temperature. First, the static performance degradation mechanism of SiC diodes is established in an ultrawide temperature range, including forward/reverse I-V characteristics and junction capacitance ( Cj ) characteristics. Second, the reverse recovery characteristics are achieved, including peak reverse recovery current ( Irm ), reverse recovery charge ( Q rr), and switching energy ( E sw), clarifying a clearer internal relationship between reverse recovery and junction temperature. Meanwhile, the aforementioned critical parameters are further analyzed on an electrical scale with normal atmosphere temperature, including switching speed range of 62.3–2054.8 A/ μ s, load current range of 6–30 A, and dc voltage range of 400–1000 V. Third, based on newly proposed power loss analysis method, the continuous operation performance of SiC diodes is quantified and analyzed in actual cryogenic converters. The excellent temperature dependence indicates that SiC diodes have great superiority for extreme applications. Importantly, SiC mosfet 's body diode shows the great potential to operate as a freewheeling diode in the compact converter, especially at cryogenic temperature.

This paper evaluates the thermal characterization of late generation SiC schottky diodes. 600 V/650 V SiC diodes from 3 well-known manufacturers are tested: Wolfspeed, Infineon and Rohm. A comprehensive study is performed for a wide temperature range from 20 °C (room temperature) up to 500 °C, aiming to find the absolute maximum parameters of SiC schottky diodes at extremely high temperature environments. Both static and dynamic characterizations are evaluated and explained. TCAD simulations are proposed to express the abnormal phenomenon occurred in test results, especially the mechanism of hole carrier transportation in extremely high temperature. This work exhibits the performance of SiC schottky diodes for high temperature application conditions.