A critical issue with the SiC UMOSFET is the need to develop a shielding structure for the gate oxide at the trench bottom without any increase in the JFET resistance. This study describes our new UMOSFET named IE-UMOSFET, which we developed to cope with this trade-off. A simulation showed that a low on-resistance is accompanied by an extremely low gate oxide field even with a negative gate voltage. The low RonA was sustained as Vth increases. The RonA values at VG=25 V (Eox=3.2 MV/cm) and VG=20V (Eox=2.5 MV/cm), respectively, for the 3mm x 3mm device were 2.4 and 2.8 mWcm2 with a lowest Vth of 2.4 V, and 3.1 and 4.4 mWcm2 with a high Vth of 5.9 V.
In this paper, we demonstrate the effect of dc substrate bias on high-rate deposition of microcrystalline silicon (μc-Si) films by using a high-density microwave plasma source. Film depositions are performed at a high silane concentration of 67% (deposition rate of ∼ 60 Å s−1) with a low substrate temperature of 250 °C. The μc-Si films deposited under appropriate negative dc substrate bias exhibit improved film crystallinity, mass density and reduced defect density along with thinner amorphous silicon incubation layer at the initial growth stage. These can be attributed to the beneficial effect of moderate ion bombardment as well as the less contribution of harmful short-lifetime radicals to film growth.
Ultrahigh voltage SiC bipolar devices more than 13 kV were developed, and their package technology was investigated. As a result, we have succeeded in creating a 13kV level PiN diode without forward voltage degradation by using 4° off substrates and a 15kV p-channel IGBT with a low differential specific on-resistance (R diff,on ) at high temperature. Moreover, the results reveal that the nano-tech resin, improved resin and Si 3 N 4 DBC substrate are the best materials for package at high temperature and ultrahigh voltage.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.