Влияние низкодозного протонного облучения на характеристики инжекционных диодов на основе 4H-SiC

The effect of low-dose proton irradiation (irradiation dose 10^10–1 . 8 × 10^11 cm^–2) on the capacitance–voltage, forward current–voltage, and reverse-recovery characteristics of 4 H -SiC p – n _ o junction diodes is studied. Irradiation is performed with 1.8-MeV protons through a 10-μm-thick Ni-film (the proton energy and Ni-film thickness were chosen so that the projected proton range in silicon carbide is approximately equal to the p – n _ o junction depth). It is shown that proton irradiation in the above doses (i) does not change the concentration of majority carriers, (ii) leads to a dramatic decrease in the lifetime of nonequilibrium carriers (at a low injection level) (by several tens of times at the highest irradiation dose), and (iii) decreases the reverse-recovery charge at a high injection level (by up to a factor of 3 at the highest irradiation dose).

Development of Low RON,Diff, 12 kV, 4H-SiC GTOs For High-Power and High-Temperature Applications

In this paper, we report our recently developed 1 × 1 cm2, 12 kV SiC GTOs with a very low differential on-resistance (RON,Diff) of 4 mΩ·cm2 with respect to the device active area at high injection level current of 100 A/cm2 or higher, which is more than a 40% reduction from our previously reported work. This significant reduction in the on-resistance was attributed to an improvement of carrier lifetime in the SiC bulk region. The SiC GTO was wire-bonded and attached to a high-voltage package before the high-temperature measurement. Forward characteristics of the device were then measured using a Tektronics 371 curve tracer from room temperature up to 400°C. Over the temperature range, the RON,Diff of the 4H-SiC GTO increased modestly from 4 mΩ·cm2 at 20°C to 4.7 mΩ·cm2 at 400°C, while the forward voltage drop at 100 A decreased slightly from 3.97 V at 20°C to 3.6 V at 400°C. The gate to cathode blocking voltage (VGK) was measured using a customized high-voltage test set-up. The leakage current was measured 0.66 μA at a VGK of 12 kV at 20°C.

Unified model for p-n junction current-voltage characteristics

Current-voltage p-n junction characteristics have been analyzed mainly at low injection levels. The high injection level region of the I/V characteristic allows the possibility of determining basic parameters of the semiconductor material, like the bulk doping concentration and charge carrier lifetime. Based on a new theoretical model of the p-n junction characteristics, valid for both low level and high level regions, a new general equation of the p-n junction is presented. It can serve for parameter extraction of semiconductor devices.