Inversion layer carrier concentration and mobility in 4H-SiC metal-oxide-semiconductor field-effect transistors

Free electron concentration and carrier mobility measurements on 4H-SiC metal-oxide-semiconductor inversion layers are reported in this article. The key finding is that in state-of-the-art nitrided gate oxides, loss of carriers by trapping no longer plays a significant role in the current degradation under heavy inversion conditions. Rather, it is the low carrier mobility (maximum similar to 60 cm(2) V-1 s(-1)) that limits the channel current. The measured free carrier concentration is modeled using the charge-sheet model and the mobility is modeled by existing mobility models. Possible mobility mechanisms have been discussed based on the modeling results. (c) 2010 American Institute of Physics. [doi:10.1063/1.3484043]